2005 EnergyValue Housing Award Gold-Winning Best Practices by NAHB Research Center

NAHB Mission Statement The NAHB Research Centerâ&#x20AC;&#x2122;s mission is to promote innovation in housing technology to improve the quality, durability, affordability, and environmental performance of homes and home building products. About the NAHB Research Center Created in 1964 as a subsidiary of the National Association of Home Builders (NAHB), the NAHB Research Center has established itself as the source for reliable, objective information and research on housing construction and development issues. The Research Centerâ&#x20AC;&#x2122;s unique relationship with the housing industry, and breadth of technical expertise, provide an unrivaled depth of understanding of the housing industry, and access to its business leaders in fulfilling clientsâ&#x20AC;&#x2122; research needs.

Notice This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of nay information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. NREL subcontract number ADO-4-444-01.

ACKNOWLEDGMENTS In a manner similar to the EVHA gold-winning homes that are conceived, designed, and constructed by a dedicated team of experts, this publication became whole through the significant contribution of the following individuals and companies: Financial support from the U.S. Department of Energyâ&#x20AC;&#x2122;s Building America Program and technical guidance from Paul Norton of the National Renewable Energy Laboratory; writing by Jeannie Leggett Sikora; technical direction from Joe Wiehagen and Tom Kenney of the NAHB Research Center; editorial review by Eryn Belt of the NAHB Research Center; artistic direction from Anne Holtz and Edy Crane of the NAHB Research Center; document preparation by Pamela Eggleston of the NAHB Research Center; insight from the 2005 EVHA Judges including Steve Baden of RESNET, Dave Richmond of ECCI, Peter Pfeiffer of Barley + Pfeiffer Architects; W. Orlo Stitt of Stitt Energy Systems, Michael Lubliner of Washington State University Energy Program and Paul Norton of NREL; and especially the 2005 EVHA gold-winning builders that contributed their time and review to this document including: Jammie and Rob Sabin of Aspen Homes, Chester Steinhauser of Casa Verde Builders, Don Ferrier of Ferrier Builders, Walt Holton of Holton Homes, Vernon McKown of Ideal Homes, John Wesley Miller of John Wesley Miller Companies, Justin Wilson of McStain Neighborhoods, Joyce Mason of Pardee Homes, and Tony Grahame of Yavapai College.

Acknowledgments

FOREWORD Quality and energy efficiency are two sides of the same coin. Building an energyefficient home means building a high quality, comfortable, and durable home. The U.S. Department of Energy's Building America Program researches methods to achieve high levels of energy savings in the nationâ&#x20AC;&#x2122;s homes; the EnergyValue Housing Award (EVHA) winners are achieving many of these goals today. The winners are progressive builders who have recognized that building high quality, energy-efficient homes sets them apart from the competition. It is not only the right choice for the homeowners and the environment; it is a profitable choice as well. There are many ways to build a high quality, energy-efficient home. EVHA goldwinning home designs respond to the local climate and market as well as reflect each builder's preferences. Each winning builder has developed a combination of techniques and technologies that works well for them. There are commonalities among the builders, but there are also many differences demonstrated in the designs presented here. Perhaps the only universal theme is the use of a systems approach to home design. A systems approach involves a comprehensive examination and analysis of the overall design, construction techniques, and business practices used to build a home. The systems approach recognizes the interactions among the myriad aspects of the building site, the envelope, and various mechanical systems to design the home as a well-integrated whole. It also examines the role of trade contractors and the interaction among them. For example, building a tight house often requires the cooperation of carpenters, insulators, plumbers, HVAC technicians, and electricians. Any company can improve the quality and efficiency of its homes. In this report, the EVHA winners offer tips on getting started. You will likely hear, "This is how I have always done it," many times before the message that there is a better alternative becomes part of your company's culture. You will need to connect with the right people in your area (resources are given at the end of this report) and you may have to learn new techniques and technologies. But these requirements are secondary â&#x20AC;&#x201C; they will follow naturally once the primary change is made: Make a commitment to build a better home! And, after youâ&#x20AC;&#x2122;ve made the commitment, get the recognition you deserve by applying to become the next EnergyValue Housing Award gold winner. Paul Norton, EVHA Judge and Senior Engineer National Renewable Energy Laboratory

Foreword

iii

TABLE OF CONTENTS INTRODUCTION ........................................................................................................ 1 GOLD AWARD WINNERS: Aspen Homes of Colorado, Inc. ......................................................................... 3 McStain Neighborhoods ..................................................................................... 7 Holton Homes .................................................................................................... 13 Ideal Homes ....................................................................................................... 19 Yavapai College Construction Technology Program..................................... 23 Pardee Homes ................................................................................................... 29 Casa Verde Builders ......................................................................................... 33 Ferrier Builders, Inc. ......................................................................................... 39 John Wesley Miller Companies........................................................................ 45 RESOURCES ......................................................................................................... 49 GLOSSARY ............................................................................................................ 57

Table of Contents

INTRODUCTION For a decade, the EnergyValue Housing Award (EVHA) has recognized builders that voluntarily incorporate energy efficiency into the design, construction, and marketing of new homes. The winners are unique builders that are willing to modify construction practices, incorporate new technologies, and forge new trade and manufacturer relationships to improve the built environment. In an era in which environmentalists are often pitted against industry, the EVHA and the builders that enter and win the competition, are refreshing. “By employing a systems engineering approach, everyone wins,” says Mike Lubliner, energy specialist at Washington State University and longtime EVHA judge, “the customers, the environment, and the builder’s bottom line. As an EVHA judge, I’ve seen the level of energy efficiency and the use of a systems approach become stronger every year.” Although each company employs a unique approach to energy-efficient home building, all of the 2005 EVHA gold winners incorporate a comprehensive approach to building design and construction that considers the impact of design decisions on the performance of the whole building. Each company has extensively researched the underlying science that makes houses function— taking advantage of expertise available from national programs such as Building America, local energy consultants, the Internet, and educational programs at national and local venues. Armed with a fundamental understanding of how houses work, EVHA gold-winning builders employ a team effort to incorporate energy efficiency into a home from design through occupancy. EVHA builders provide exceptional value to their customers by implementing climate-appropriate methods to build highly-efficient homes that are comfortable and durable. These builders not only “raise the bar,” but often are setting the bar with new ways of thinking and constructing homes. This book is intended for home builders that wish to learn more about incorporating climate-specific, energy efficiency home building practices. It is hoped that, by following the path of the gold-winning EVHA builders, other home builders can endeavor to become the trailblazers of the next 10 years.

Introduction

Aspen Homes Loveland, Colorado Affordable Home – Cold Climate

uilding energy-efficient and affordable homes was a founding principle of Aspen en Homes. As a builder for the affordable market, Aspen Homes needs to justify the cost of all energy-efficiency decisions. Luckily, according to company president Jammie Sabin, there are many very cost-effective, efficient measures that can be implemented easily.

Valuable Decisions According to Sabin, a strong air sealing program and an innovative approach to insulation are among the most cost effective energy-efficiency measures that the company has adopted. However, he warns, “If you do just those things [and not a whole systems approach], you can end up with more problems. You can’t do insulation and air sealing alone.” Aspen’s upgraded insulation system includes an R-15 blown-in blanket system and R-5 foam sheathing taped at the seams. The company likes the ease with which the blown-in system fills wall cavities. The exterior rigid foam not only provides a continuous layer of insulation, but with seams taped, it also serves as an exterior air infiltration barrier.

Aspen Homes

Sealing Details Snapshot of Energy Features Foundation: Conditioned crawlspace with concrete floor; R-19 wall insulation Wall Construction: 2x4 at 16 inches-on-center with twostud corners and ladder blocking at interior partitions Wall Insulation: R-15 blown-in blanket system plus R-5 foam sheathing with seams taped Ceiling/Roof Construction: Trusses Ceiling/Roof Insulation: R-38 blown cellulose Windows: Low-e; U-0.35; SHGC 0.32 Air Sealing: See Sealing Details section Blower Door Test: 3.25 ACH50 Heating Equipment: AFUE 92.6 condensing gas furnace Cooling Equipment: None Ducts: 100 percent in conditioned space; Manual J calculations; Seams sealed with mastic; Centralized returns with transfer grilles across interior doorways Duct Losses: 98 cfm total at 25 Pascals; No leakage to exterior Ventilation: 30 cfm fan operated by air cycler with humidistat Hot Water System: 82 percent efficient tankless gas water heater Solar Hot Water: None Solar PV System: None Lighting: 1 permanent fluorescent fixture; 21 incandescent fixtures; 1 tubular skylight Appliances: ENERGY STAR refrigerator (432 kWh/yr) and dishwasher (371 kWh/yr) HERS Score: 91.0 Construction Cost: $41 per s.f.

In addition to the exterior foam air barrier, Aspen Homesâ&#x20AC;&#x2122; extensive air sealing package includes placing sill sealer between the masonry foundation and the sill plate, foam sealing voids in the rim joist, foam sealing mechanical penetrations, caulking around window and door frames, weather stripping around the attic hatch and exterior doors, caulking top and bottom plates, and gluing the drywall to the top and bottom plate with subfloor adhesive. To prevent air infiltration through a notoriously leaky area, exterior walls around showers and baths are first insulated with open-faced fiberglass batts and then covered with insulating structural sheathing. The sheathing is sealed with waterproof caulk at each seam and at the top and bottom plate.

Affordable Ventilation

Aspen Homes understands the importance of providing fresh air to a home that is tightly sealed. To do this inexpensively, the company installs a small duct to bring fresh air from the outdoors to the return side of the air handler. A separate controller operates the air handler on a predetermined schedule to supply adequate ventilation.

In Hot Water Another value-added feature that Aspen selected for this home is a tankless water heater. Although the equipment costs about three times more than does a typical tank-type water heater, Aspen believes the system is a benefit that is well worth the investment. According to Aspen, the increased performance (the system supplies endless hot water) and efficiency, coupled with reduced callbacks and long-term energy cost savings, offset the higher initial cost.

Domestic hot water is produced efficiently with a tankless gas water heater.

Aspen Homes

A Very Short Basement Instead of a conventional crawlspace or basement foundation, Aspen builds “a very short basement,” as Sabin puts it. The system effectively eliminates the moisture problems often associated with conventional crawlspace design. The water-managed system, which costs more than a conventionally-constructed crawlspace but less than a full basement, includes a capillary break below the slab, a layer of six-mil poly, and a drain. Walls are insulated with R-19 fiberglass batts and a supply register delivers conditioned air to keep the crawlspace close to the same temperature as the house. A jump duct to the interior provides a means for balancing pressure and for return air flow. Subsequently, the dry, semiconditioned area is perfect for mechanical equipment and as storage for the homeowners. A passive radon control system ensures that soil gases are exhausted from the home.

Model HVAC System

Overview of insulation details including use of exterior rigid foam and insulated crawlspace.

Using a conditioned crawlspace simplifies the process of keeping ductwork and mechanical equipment in conditioned space. But the twostory design still requires foresight for efficient mechanical system planning. “We make sure the duct layout is planned at the same time as the framing and joists” according to Sabine. “Because we do our own design, and because we build entry level homes [with simple rooflines and building shapes], it is a little easier.” During the design phase, Aspen’s HVAC contractor performs Manual J calculations and modifications to the house plan are made at that time, if necessary, to ensure the HVAC system will function well. A centrally-located furnace keeps duct runs short and, where possible, supply ducts are kept straight with minimal curves and branching. Central returns and transfer grilles across interior doorways equalize pressure throughout the house. The company requires that there be no more than a three-Pascal pressure difference across any interior doorway in order to ensure adequate circulation throughout the house.

A jump duct between the conditioned crawlspace and the living area provides return air flow from the crawlspace.

Aspen Homes

Quality Control In addition to the third-party inspections conducted by local energy consultant BuiltWright, Aspen Homes performs internal HVAC inspections. The company uses a checklist to quickly and systematically identify target areas for examination. As part of the E-Star Colorado rating process, BuiltWright tests the ducts after HVAC rough-in and completes a blower door test and final energy rating just before completion. Insulating sheathing that is sealed at the top and bottom plates is used to prevent air infiltration at baths and showers.

A Work in Progress To refine their building methods, Aspen has collected data from past homes. As Sabin states, “We are always looking to improve. I can’t really say what we’re going to do tomorrow. If we have thought of it, and can make it cost effective, we are putting it into action.”

All or Nothing Sabin’s advice for a company that wants to start building energy efficient homes is to be fully committed and “barrel ahead full speed.” Sabin says, “You can’t take a systems approach by going in small steps. You can’t do it halfway, because you end up with problems.” Exterior foam sheathing, taped at seams, provides an additional R-5 insulation and an air infiltration barrier.

Rim joist detail includes foam sealing and R-19 fiberglass batt insulation.

Aspen Homes

To sort through the process, Sabin recommends starting with a state energy-efficiency organization, such as E-Star Colorado, if available or a national organization, such as Building America. He also suggests finding out who the leading builders are in your climate and reviewing their approach. “Call them and talk to them, they are usually pretty open,” he says.

McStain Neighborhoods Boulder, Colorado Custom/Demonstration Home – Cold Climate

cStain Neighborhoods has been a leader in energy- and resource-efficient home building in the Boulder market for years. As a production home builder of about 400 homes each year, the company is constantly searching for new building materials and methods to improve its product.

Practice Makes Perfect McStain’s Discovery House, the third in a series of demonstration homes designed to test new products and processes in the field, has a number of changes to the company’s standard practices incorporated within. A key objective was repeatability. While the company already implemented many energy-efficiency measures, they wanted to know what else could be done, both practically and economically, through a systems engineering approach, to further reduce natural resource consumption in a production home building environment.

McStain Neighborhoods

Designing Minds

Snapshot of Energy Features Foundation: R-11 insulated basement and crawlspace; R7 continuous under-slab insulation Wall construction: 2x6 walls at 24 inches on center Wall Insulation: R-19 cavity insulation plus R-4 rigid foam Ceiling/Roof construction: Trusses and dimensional lumber Ceiling/Roof Insulation: R-44 blown cellulose Windows: Low-e windows; U-0.35; SHGC 0.34 Air Sealing: Airtight drywall approach Blower Door Test: 1.82 ACH50 Heating Equipment: Combined space and water heating system (90 percent combined efficiency) with hydronic coil in air handler serving 1st and 2nd floors and in-floor radiant heating in basement Cooling Equipment: Two whole-house fans; SEER 19 air conditioner Ducts: 100 percent in conditioned space; Sealed with mastic; Central returns with transfer grilles to maintain equal pressure across doors Duct Losses: 20 cfm to exterior at 25 Pa Ventilation: 150 cfm heat recovery ventilator Hot Water System: High-efficiency combined space and water heating system supplemented with solar energy (90 percent combined efficiency) Solar Hot Water: Three, 4x8 solar thermal collectors provide preheated water to the combined space and water heating system; Energy stored in 180-gallon drainback storage tank Solar PV System: None Lighting: 100 percent fluorescent; Tubular skylight for natural lighting; Majority of fixtures accept only 2- or 4-pin fluorescent bulbs Appliances: All appliances labeled ENERGY STAR; Refrigerator (372 kWh/yr); Washer (294 kWh/year); and Dishwasher (643 kWh/yr). HERS Score: 93.8 Construction Cost: $166 per s.f.

“It is evident that design and energy efficiency goes hand in hand, and that one cannot be separated from the other,” says Justin Wilson, environment sustainability manager for McStain. Wilson and others at McStain worked closely with Building Science Corporation (BSC) under the Building America program to design and construct the home. BSC engineers performed advanced modeling to help select materials and systems. The engineers also helped design the custom solarassisted space and water heating system. The most valuable lesson that McStain gained from the Discovery House was the design team concept where in-house specialists work with engineers, architects, and subcontractors to select and implement energy-efficient design features. Wilson says, “When you push the envelope, there’s an educational aspect for everyone. We had to bring the subcontractors on board way before the start of construction to show them the pieces and how they go together. One of the things we found is that our subs want to be challenged. The team approach made a tremendous difference in our homes.”

Trying New Things

The first new step in construction of the Discovery House was the installation of a capillary break between the footing and foundation to prevent the migration of moisture between the elements. For the capillary break, McStain chose 1/8inch EPDM roofing material because it could easily be installed by the foundation crew. A sprayed-on membrane would have been suitable, but it required the scheduling of another work crew. The capillary break—required for the home’s American Lung Association Health House certification—added very little time to the construction process and about $200 to the construction cost. McStain’s all-fluorescent lighting package includes many stylish fixtures.

McStain Neighborhoods

A Dual-Purpose Floor System The Discovery House’s basement floor system is an example of a product that McStain has adopted for all of its new homes. For the expansive soils on which the company builds, McStain had been using structural concrete slabs, which require a void material underneath. To eliminate the use of the biodegradable material previously used (that could retain moisture), the company tried a foam honeycomb product (called GeoVoid) that is covered with rigid foam before the reinforced concrete slab is poured. The new system not only compresses to McStain uses a basement floor system that absorbs absorb the forces of the expansive soil and resists forces of expansive soils. R-7 continuous insulation is moisture, but it also adds R-7 continuous insulation installed over the honeycomb system before reinforced concrete floor is poured. under the floor—which becomes especially beneficial for the in-slab radiant floor heating. The company’s positive experience with incorporating the product into the construction process, as well as its benefits for efficiency and building durability, led them to make the system standard practice.

Learning from Experience Previous testing had shown that a primary area of air infiltration was at the sill plate foundation juncture. To combat this air infiltration, the company tried an innovative sill sealing product—a T-shaped material that fits like a gasket between the foundation and sill plate. The product’s two self-adhering flanges stick to the exterior concrete foundation wall and the rim joist. Another method employed to achieve the home’s impressive 1.82 ACH50 blower door test result was the Airtight Drywall Approach in which drywall is glued to the top and bottom plates of exterior walls and to window and door framing. Flanged airtight electrical boxes, which are sealed to the drywall, complete the interior air barrier. Sill seal material has self-adhering flanges to further To correct another notorious spot for air infiltration, prevent air infiltration at sill-foundation connection. McStain set the rim joist back ¾-inch to provide space for a continuous band of rigid insulation. Next, to provide mechanical ventilation to the tightly-constructed home, a 150 cfm heat recovery ventilator (HRV) was used to draw interior air from the bathrooms and the laundry room and to deliver fresh outdoor air to the return side of the air handler. The HRV, which recovers energy from the outgoing air stream to temper the incoming air stream, operates at a low speed continuously, and is boosted to high speed for 20 minutes whenever a control switch is operated in one of the bathrooms.

McStain Neighborhoods

Wall System by Trial and Error Because this home was a demonstration and experiment for the company, details needed to be worked out prior to construction. For the wall assembly, which included 24-inch on-center framing and a rainscreen approach to siding installation, McStain worked with its framing contractor to build a full-scale mock-up. This mock-up helped identify potential problems and answer questions before field installation. The exercise proved invaluable; it expedited a construction process that might have otherwise been significantly delayed.

A Smart Approach to Moisture Control Rim joist is set back from edge of sill plate to make room for rigid foam insulation.

For the vapor barrier, McStain used a hybrid material called MemBrainâ&#x201E;˘ that varies its permeability to water vapor with climatic conditions. During the winter at times of low relative humidity, the material blocks the flow of water vapor. During times of high relative humidity, the material allows water vapor to pass through, thereby permitting drying of a wetted wall.

Natural Breezes In addition to south-facing overhangs to shade windows and a retractable awning over the south patio, numerous features reduce the need for air conditioning. Located high in the vaulted ceiling of the great room are three motorized, thermostatically-controlled (with manual override) windows that draw hot air outside by the chimney effect. A screenedin porch on the north side features a Murphy bed to provide a cool place to sleep. An outdoor kitchen is not only a pleasant place to prepare meals, but also reduces the heat generated by cooking indoors. Adding to the natural cooling design features are two wholehouse fans to draw outdoor air inside during the often cool nights of summer. On the rare occasions when mechanical cooling is needed, a 19 SEER (the highest available at the time of construction) air conditioner takes over.

Mock-up of wall assembly built by contractors before house construction.

Completely Energy-efficient Heating To take advantage of the abundant sunshine in Boulder, McStain worked with BSC and a local solar company to design a combined space and domestic water heating system that is preheated by hot water from solar thermal collectors. Hot water produced by three rooftop thermal collectors is stored in a 180-gallon storage tank and supplies domestic hot water, radiant floor heating for the basement, and a hydronic air handler for the first and second floors. When additional heat is needed, it is supplied by a Lennox Complete Heat system at 90 percent efficiency.

McStain Neighborhoods

The team is still trying to fine-tune the custom system and work out the bugs. McStain was hoping the system could be put into production but, “It is probably further off than we hope,” says Wilson.

Putting it on the Plans McStain worked with partner BSC to carefully design the air distribution system. Calculations determined airflow to each room and the duct layout became part of the blueprints. “When there is a problem, we can look at the prints to try to figure out where the issue is. For the HVAC contractors, the system has reduced callbacks,” says Wilson. “Besides,” he adds, “It holds subcontractors accountable for every installation.” Wilson encourages builders to not only have HVAC contractors perform duct design and layout according to ACCA Manual D, but also to put duct layout on the blueprints. Numerous features such as south-facing Two central returns, combined with transfer grilles across window overhangs provide natural cooling. doorways, helps evenly distribute conditioned air throughout the house. All ducts are located in conditioned space and sealed with mastic to ensure that airflow is delivered as designed.

Comprehensive Testing Although the ENERGY STAR® program requires that large production builders like McStain test the efficiency of only a sampling of homes, the company elects to test every single home it builds. “Testing every unit,” says Wilson, “proves efficiency and holds subcontractors accountable.” McStain uses a third party to not only conduct blower door testing, but also to test the tightness of the duct system, the airflow to each room, and the ventilation system. For this prototype home, there will be ongoing tests including tracer gas (to track ventilation) and monitoring of electricity, water, and gas consumption. Raised heel roof design allows full height insulation over top plate and simplifies construction of extended overhangs for shading.

McStain Neighborhoods

Advice to Newcomers Wilson recommends that builders in cold climates who want to build more energy-efficient homes start with combustion safety. Sealed combustion appliances, he points out, get make-up air from outdoors and do not rely on leaky houses to provide air for combustion. Therefore, he concludes, the equipment “solves a big problem down the road when you build a tighter house.”

Three solar thermal collectors provide hot water for space heating and domestic use.

His next piece of advice is to phase any changes incrementally. “Don’t think you can do it all in a day. We’ve been doing this over 10 years … it can be frustrating to try to do everything at once. Expect failure.”

Once You Get There… Wilson also had some sage advice for builders that are ready to apply for the EnergyValue Housing Award. He described the application process as long and difficult, but also as a positive experience. He suggests assembling a team of people that includes representatives of the construction, marketing, and sales departments, no matter how small the company is, and making one person accountable for oversight. He also suggests keeping records and photos during construction to facilitate the process—and to not forget that the application must be submitted in triplicate.

Example of transfer grille to provide a return air path.

McStain Neighborhoods

Holton Homes Boise, Idaho Production Home – Cold Climate

olton Homes employs a practical approach to home building. The company strives rives to understand how a building responds to its climate and how to provide the best value for the energy-efficiency investment dollar. Simply stated, Holton Homes provides an “excellent example of systems engineering…a really good package” according to the EVHA judges.

From the Ground Up Holton Homes’ energy-efficient building system starts at the foundation: an unventilated, insulated, and sealed crawlspace. The semi-conditioned area is built to stay dry—something, according to the builder who has been in a lot of wet crawlspaces, that cannot be said of many crawlspaces. Holton Homes decided to build conditioned crawlspaces after gaining a lot of experience with wet, unconditioned crawls. During the “mold scare” in 2000, Holton Homes realized that it needed to know more about mold. Walt Holton, company vice president, read as much as he could and attended local seminars (sponsored by the Idaho Energy Division). Eventually, Holton Homes joined forces with a national restoration company that performs water damage repair work for insurance companies. After spending a lot of time in wet crawlspaces and learning how mold, water, and structural drying work, Walt Holton developed a crawlspace construction method that would be durable for the long term.

Holton Homes

Snapshot: Energy Features Foundation: Crawlspace insulated to R-16 Wall construction: 2x6 advanced framing Wall Insulation: R-21 high density fiberglass battt Ceiling/Roof construction: Truss-framed flat and vaulted ceilings Ceiling/Roof Insulation: R-38 BIBs on flat and vaulted ceilings Windows: Low-E; U-0.33; SHGC 0.42 Blower Door Test: Blower door test 3.1 ACH50 Heating Equipment: 91 AFUE gas furnace Cooling Equipment: 12 SEER Ducts: 75 percent ducts in conditioned crawlspace, 25 percent ducts in attic—sealed, insulated, and buried under insulation Duct Losses: Less than 5 percent air handler flow Ventilation: Continuous exhaust from conditioned crawlspace with one-way passive inlet from living area; make-up air provided to return side of HVAC Hot Water System: Gas tank-type water heater EF 0.67 Solar Hot Water: None Lighting: Half of all lighting fixtures fitted with fluorescent bulbs Appliances: ENERGY STAR dishwasher Solar PV System: None HERS Score: 90.1 Construction Cost: $62 per square foot

Construction detail showing Holton Homes’ insulated crawlspace design.

Holton Homes

At first, code inspectors were dubious. However, as Holton points out, conditioned crawls are now a part of the International Residential Code (Section R408.2 of the 2003 IRC)—so it is easy to simply point to the codes when requesting inspector approval. For details about how to build a conditioned crawlspace, see the materials under Crawlspaces in the Resources Section.

Less is More One of the most cost-effective, energyefficiency measures the company employs is advanced framing. The system not only uses less lumber and allows for more insulation in wall cavities, but also reduces drywall cracks and decreases installation time. By implementing advanced framing techniques that save on lumber costs, the builder can use larger 2x6 studs instead of the conventional 2x4 framing and thereby leave more room for a higher R-value insulation in the wall cavity. Initially, Holton’s framing crew “freaked out” about using the advanced framing techniques. However, as Holton explains, after working through the method on one house, there were no more complaints. Although Holton had to talk the crew into giving the system a try—and to not raise their prices for that first house—the crew now loves the system. They carry less lumber and “earn money with their brains rather than their backs.” Holton also cautions that, in order to be successful with advanced framing techniques, the contractor needs to be “a thinker rather than just an assembler.” The top-notch crew with which Holton Homes has had a relationship for about 10 years was the perfect partner for implementing the new system. Holton describes standard header sizing practices as “like killing a fly with a sledgehammer,” and, instead, espouses calculating roof loads and sizing headers according to the International Residential Code (see Section R602 for wood wall framing requirements). Proper sizing reduces framing costs and permits more insulation above wall openings than typical, over-sized headers.

Finally, code inspectors wanted the company to provide engineering approval for the advanced framing designs. However, it was easy to show inspectors the references in the code books and eliminate the need for engineering. For more information and details about advanced framing techniques, review the materials under Advanced Framing in the Resources Section.

Bonus “Saunas” A Realtor® friend of the builder describes bonus rooms as “built in saunas” in most houses—due to their proximity to hot attics and roofs and their tendency to get extremely warm. Holton Homes uses a radiant barrier attached to the back side of insulated kneewalls to prevent heat build up in bonus rooms.

Insulated, unvented crawlspace under construction.

Sizing it Up When sizing heating and cooling equipment, Holton Homes takes extra care. The company understands that over-sized cooling equipment reduces equipment life. In its homeowner’s manual, Holton Homes likens over-sized equipment to intown driving, where a car gets poor mileage because the engine runs in short bursts rather than in sustained operation. Properly sized equipment, they know, will run longer at higher efficiency and will keep humidity under control and, therefore, homeowners more comfortable.

Kneewall with radiant barrier detail in bonus room.

Because of a relatively short cooling season and Idaho Power’s very low electricity rates, the company feels it cannot justify very high efficiency air conditioning equipment at this time; they use a 12 SEER system. However, the company vows to re-evaluate electric rates and the price of higher SEER equipment and to select the higher efficiency equipment when it is more cost effective for the homeowner.

In-line framing using a single top plate and larger stud spacing.

Holton Homes

The Ducts Have It Holton Homes recognizes that ductwork is often the most wasteful (and neglected) component of home heating systems. A full page of its homeownerâ&#x20AC;&#x2122;s manual is dedicated to describing duct system efficiency. Holton Homes, along with its mechanical subcontractor, seals every seam, crack, and gap in the sheet metal ducts with mastic. Ducts must leak less than five percent of the rated air handler flow to meet Holtonâ&#x20AC;&#x2122;s standards. By keeping Duct boot showing mastic sealing. supply ducts in the sealed and insulated crawlspace, any duct loss tends to add energy to the home rather than to be lost outdoors. On certain home designs, the company continues to place some return ductwork in attics. To minimize heat loss from this return duct, they seal joints with mastic, insulate the exterior, and bury the ducts under attic insulation.

The Fresh Air Cycle Holton Homesâ&#x20AC;&#x2122; advanced air sealing measures, which add additional steps beyond the stringent local code requirements, include caulking outlets, light fixtures, and any other openings that breach the floor, wall, or ceiling after drywall installation. Local requirements for sealing before drywall include caulking gaps in framing, foam sealing holes in framing, and filling gaps around Round duct with backdraft damper, that windows with backer rod. Blower door test results for Holton opens during fan operation. Homes ranged between 0.15 and 0.2 ACHnat compared to 0.5 ACHnat for homes built with the local code-required sealing package. Because of this low level of natural air infiltration, mechanical ventilation is installed to bring in a planned amount of outdoor air. The unique affordable ventilation system employs an exhaust fan to continuously remove air from the crawlspace. Make-up air is provided to the crawlspace by a one-way passive inlet which allows air to flow from the home into the crawlspace (but not vice versa). Next, another vent is connected from outdoors to the return side of the HVAC system to provide make-up air to the home, thereby completing the loop. The ventilation strategy ensures that the crawlspace remains at a negative pressure with respect to the house, which prevents contaminants such as radon from entering the home. Testing air pressures with the make-up air supply open and with it sealed off provides assurance that adequate make-up air is coming from the makeup air vent.

Holton Homes

Success Story After building its first ENERGY STAR® Home, the company has become an all-ENERGY STAR builder in less than three years—constructing nearly 100 homes under the program in 2004. As part of the ENERGY STAR program, three, third-party inspections throughout the construction process ensure designs are accurately executed. A Home Energy Rater inspects the project after framing to verify compliance with the plans, checks the insulation, ductwork, and air sealing for quality of workmanship, and conducts final performance testing. At the final inspection, the rater checks the final insulation and equipment and performs duct blaster and blower door tests. The duct leakage test determines how much heated or cooled air is wasted before it reaches the living area.

Looking into the Future

Careful duct sealing produces exemplary duct leakage test results.

According to the EVHA judges, Holton Homes provides an “excellent example of systems engineering …a really good package.” However, the company is not done making its houses better. The company plans to continue to evaluate new technologies and techniques to find those that will add value for costconscious buyers. In this vein, Holton Homes recently opened a subsidiary company, First General Services HVAC. By doing so, the company can avoid subcontractor markups on equipment and, therefore, bring cost-competitive, high-efficiency HVAC to their buyers.

Advice to Others Getting Started Holton Homes has always wanted to be a better home builder than the competition. They tried doing “this or that” for a while to set themselves apart, but it didn’t seem like the things they were doing were ever going to be valued by buyers. Then it clicked. A presenter at a seminar Walt Holton was attending said, “Pick something you want to be the best at and then dominate your market in it.” Holton thought about it a bit and decided that energy efficiency was as good an investment (for the homeowner) as the stock market. He then set off to make his company the leading energy-efficient home builder in the local market. Holton’s advice to new home builders that want to start building more energy-efficient homes is to take it one step at a time. Attend a seminar that teaches the whole “systems approach,” but don’t allow yourself to be overwhelmed. Start with something easy and take it one piece at a time. Set goals and finish one goal before you go to the next. For example, when the company wanted to switch to low-E windows, they simply told their suppliers what they wanted and at what price—and they were willing to find another supplier if a deal could not be struck. Some of the most cost-effective (and energy-efficient) measures that Holton implemented when his company embarked on energy-efficient construction was advanced framing (after convincing their framers not to increase the cost for the first house) and duct sealing.

Holton Homes

Ideal Homes Norman, Oklahoma Affordable Home – Mixed-Humid Climate

s the EVHA judges put it, “Ideal Homes offers a remarkable product.” And not only do they make a good home, they have an “incredible” marketing program. The program includes energy-efficiency displays in open houses, 3-D displays showing cutaways of their walls, an in-house sales representative offering training on demonstrating, and explaining energy-efficiency features, and local seminars on energy-efficiency mortgages. “If you don’t point it out to customers, you are giving it away,” says Vernon McKown, president of sales for Ideal Homes.

Making their Mark While Ideal makes its own mark by building an average of 450 energyefficient homes each year, the company is also changing the way other local builders do business. According to one EVHA judge, “[Ideal] has forced market transformation …everybody in its market is doing something with energy efficiency.”

Ideal Homes

Partners in Design

Snapshot of Energy Features Foundation: Slab; Slab-edge insulated to R-4 Wall Construction: 2x4, with advanced framing details Wall Insulation: R-15 Blown-in-Batts with R-3.5 insulating sheathing Ceiling/Roof Construction: Wood-framed Ceiling/Roof Insulation: R-30 cellulose Windows: Low-E; U-0.3; SHGC 0.36 Air Sealing: Sealing and caulking protocols Blower Door Test: 4.2 ACH50 Heating Equipment: 90 AFUE gas furnace Cooling Equipment: SEER 14 air conditioner Ducts: Sealed with mastic; R-6 insulation; None in conditioned space Duct Losses: 62 cfm to exterior at 25 Pascals; 153 cfm total at 25 Pascals Ventilation: Fan control that operates air handler on regular interval; Motorized damper for fresh-air inlet Hot Water System: Gas tank-type water heater; EF 0.60 Solar Hot Water: None Solar PV System: None Lighting: Fluorescent fixtures optional Appliances: None HERS Score: 89.3 Construction Cost: $43 per s.f.

Ideal Homes’ design division includes an architect who is nationally recognized for his passive solar and energy conserving designs. After initial designs are prepared, Ideal relies on energy consultants Guaranteed Watt Saver Systems (GWSSI) to analyze plans and recommend cost-effective energy improvements. Design considerations can include placing garages on the north, recessing and sheltering entry doors, locating brick fireplaces on the inside walls to provide thermal mass, placing large south windows for solar gain, designing open floor plans to ensure even air distribution, and providing ceiling fans to improve air circulation and decrease the need for air conditioning.

Partners in Construction

All Ideal Homes’ superintendents receive six week’s training covering all of the company’s construction techniques. The superintendents also attend workshops describing how energy efficiency adds value to homes, seminars about the effectiveness of energy features as a marketing tool, and demonstrations of the blower door test to help them understand the potential for energy loss through air infiltration. Diagnostic results are used as a measure of successful performance. For superintendents whose homes achieve outstanding performance, the company offers incentives such as additional vacation time and other perks.

Crossing the Ts The extensive training helps superintendents understand the critical dependence of house performance on installation. To reinforce this concept, Ideal Homes uses numerous quality assurance inspections and checklists, including a twice-daily jobsite walkthrough by superintendents to confirm that trade contractors are properly implementing the Ideal Homes’ energy program. For validation, Ideal contracts with GWSSI to perform onsite quality assurance inspection and blower door and duct performance testing.

Ideal Homes

Putting Its Money Where Its Mouth Is Ideal’s homes cost about three to five percent more than other homes in the local market. But, McKown points out, “We use our energy performance to get out of the commodity game. Our houses are engineered for performance and lower cost. Our houses are different.” The company backs up its claims with a guaranteed utility bill. Ideal’s homes cost between 20 percent and 30 percent less to operate than the competition. “Everyone has a utility bill,” says McKown, “and $20 to $30 per month is a lot [when factored into a 30-year] mortgage.”

Trade-Offs To keep construction cost competitive, Ideal Homes has done its homework to provide the best value for the energy-efficiency investment dollar. For example, the company worked with GWSSI to model energy savings from bringing ductwork into conditioned space and Banner displays utility bill guarantee. found a predicted savings of two percent—for a cost of $750. Therefore, they opted to keep the ducts in the attic for now. McKown explains, “It would be easier with trusses, but we are in a stickframe market and our houses are single story with a hip-roof design. We make our energy decisions based on tradeoffs.”

Affordable Fresh Air On the other hand, Ideal Homes understands the value of fresh air ventilation in a tightly-constructed home. Standard operating procedure is to “keep what’s desirable in” and “that which is less than desirable out.” When it comes to air infiltration, this means that paying special attention to air sealing and adding a fresh-air ventilation system—something rarely found in the affordable market. The affordable ventilation system consists of a controller that operates the central air handler on regular intervals. A motorized balancing damper opens to bring outdoor air to the return side of the air handler when the ventilation system is operating.

A Matter of Size

A third party performs a blower door test to check the air tightness of an Ideal Home.

Ideal Homes understands that smaller HVAC systems cost less. Therefore, Ideal asked GWSSI to size the HVAC system according to industry standards. Ideal Homes uses the money saved in HVAC equipment for efficiency features such as high-performance windows, thereby mitigating some of the added cost of energy efficiency.

Ideal Homes

The Looking Glass As another value-added energy feature, Ideal is experimenting with fluorescent lighting in its model homes. “It has really saved a lot of money on utility bills—about $17 per month in the models,” says McKown. However, the company wants to make sure the technology is ready for the mainstream homebuyer “It’s a $300 upgrade just to put [compact fluorescent] light bulbs in [conventional] fixtures,” explains McKown.

Go National

Ideal Homes uses blown-in fiberglass batts and insulating sheathing to achieve R-18.5 in a 2x4 wall.

Ideal uses the home’s HVAC air handler, a fresh air duct from the outdoors, and a programmable controller in the low-cost ventilation system.

Ideal Homes

For builders that want to get started with energy-efficient home construction, McKown suggests getting involved in a national builder program such as Environments for Living. “It’s the most economical way to get started with building science,” he says. McKown notes that it may be difficult to find a knowledgeable building scientist in your area and that the technical support provided by national programs can help you through the process.

Yavapai College Construction Technology Program Prescott, Arizona Custom/Demonstration Home – Mixed-Dry Climate

or eight years, students from the Construction Technolgy program at Yavapai College in Arizona have been designing and building energy-efficient, durable, and affordable homes that incorporate appropriate technologies. By teaching practical, hands-on skills, according to director Tony Grahame, “The students understand how to design and construct homes that work as a system and that are environmentally responsive.” The students follow building science principles outlined by organizations such as the Energy and Environmental Building Association (EEBA), ENERGY STAR®, the American Lung Associations’ Health House, Environments for Living, Building America, and Building Science Corporation.

Learning from Experience Not only is Yavapai College dedicated to teaching students, it is also dedicated to educating the community about efficient construction practices through community events. Local builders are invited to open houses, students conduct tours, and the homes are featured in advertisements and are the subject of numerous news stories.

Yavapai College

The Importance of Air Sealing

Snapshot of Energy Features Foundation: Insulating concrete forms for unvented, conditioned crawlspace Wall Construction: 2x6 studs 24” using advanced framing techniques Wall Insulation: R-21 blown cellulose with 1-inch rigid foam on exterior; R-19 rim joist cavity insulation with 2-inch rigid foam on the exterior of the rim joist Ceiling/Roof Construction: Raised heel scissor trusses and wood frame Ceiling/Roof Insulation: R-38 blown cellulose Windows: Double pane, low-e, argon gas-filled glazing; U-0.29; SHGC 0.33 Air Sealing: Airtight drywall approach; extensive sealing Blower Door Test: 1.24 ACH50 without crawlspace; 1.07 ACH50 with conditioned crawlspace Heating Equipment: 94 AFUE gas furnace; 78 percent efficient direct vent gas fireplace – sealed combustion Cooling Equipment: 12 SEER air conditioner Ducts: 100 percent in conditioned crawlspace; sealed with mastic with balanced airflow Duct Losses: 27 CFM total at 25 Pascals Ventilation: Heat recovery ventilator with HEPA filtration; Controlled by timer to ensure adequate ventilation Hot Water System: Solar with electric tank back-up water heating system Solar Hot Water: One, 4x10 flat plate collector with glycol loop; hot water stored in 80-gallon electric storage tank with integral heat exchanger Solar PV System: None Lighting: All standard fixtures fitted with fluorescent bulbs; 12 permanent (pin-type) fluorescent fixtures; two tubular skylights Appliances: ENERGY STAR dishwasher (282 kWh/yr); Electric oven/stovetop HERS Score: 92.9 Construction Cost: $83 per square foot (includes labor of 30 percent subcontractors and 70 percent provided by students)

According to Grahame, one of the most important energy-saving practices in home building is air sealing. “You can’t have an energy-efficient house without having an airtight thermal boundary. Of course, once you have an airtight structure, you have to recognize the need for ventilation and humidity control. But this is easily attained with mechanically controlled ventilation.” Yavapai’s students perform air sealing at every step of the construction process, from foundation to drywall, resulting in an impressive blower door test result of 1.24 ACH50 (1.07 ACH50 if the crawlspace is included in the calculation). Having a tight building envelope and highly insulating walls allows the students to cut energy costs by downsizing the mechanical equipment.

Foundation Sealing

To achieve this level of air tightness, Grahame and the students start from the ground up. When the insulating concrete forms (ICFs)—which remain in place to serve as insulation after the foundation is poured—are set for the foundation, sealant is applied at the joints between the forms, in an effort to eliminate every potential source of air infiltration. Although not intuitive, Grahame says, “There is still potential for air leakage through grouted stemwalls.” The foundation for the unvented crawlspace is treated as part of the thermal envelope of the building and is also air sealed from the exterior. Atop the foundation, a foam sill sealing product is used before the sill plate is attached. Flooring adhesive is applied to the joint between the rim joist and sill plate.

Rim Joist Sealing

Student worker applies sealant between each insulating concrete form.

Yavapai College

To prevent air infiltration and insulate a notoriously leaky area, the rim joist is set back from the edge of the foundation in order to accommodate an additional layer of rigid foam. The foam is sealed to the foundation and the

subfloor to serve as a barrier to air infiltration. Flooring adhesive is applied between the bottom plate of walls and the tongue-and-groove plywood subfloor for additional air sealing.

Wall Sealing Two distinct air barriers control air infiltration from the exterior: OSB sheathing is glued to all studs and plates; and housewrap is taped and lapped at seams, wrapped around openings, and caulked at the top and bottom to the OSB sheathing.

Rim joist detail showing gasket between

the sill plate and foundation and adhesive The interior air barrier is achieved by employing the between the rim joist and sill plate. Airtight Drywall Approach, in which drywall is glued to the wood frame. In this method, workers apply flooring adhesive to seal drywall to the top plate and around any wall openings. In order to find a more convenient method of sealing the bottom edge of the drywall to the floor, the group used tape to seal drywall to the plywood floor deck. After drywall installation, all junction boxes and recessed lights are caulked to the drywall before cover plates are installed. All recessed ceiling lights are airtight and rated for insulation contact.

Finishing Sealing Touches All electrical, plumbing, and mechanical penetrations to the exterior are sealed with low-expanding foam. In fact, the same penetrations are sealed in the interior framing to prevent air movement within the wall cavity. Window and door rough openings are insulated first with fiberglass batt insulation and finished with low-expanding foam. All electrical wires penetrating junction boxes and other small holes in the boxes are sealed with masticâ&#x20AC;&#x201D;the workers use their hands (covered with plastic gloves) or small brushes to apply the gooey substance.

Insulated and sealed foundation detail on ICF stemwall.

Insulation to the Max Several construction details maximize the insulation value of the tightlybuilt walls. The ICF foundation insulates the crawlspace to R-16. The rim joist cavity is insulated with fiberglass batts to R-19; with an additional two inches of rigid foam insulation on the rim joist exterior. Advanced framing details and one inch of exterior rigid foam insulation minimize thermal bridging through the 2x6 stud walls, which are sprayed with R-21 cellulose insulation. Insulating the garage slab not only shows students how to construct an insulated slab, but also helps the south-facing garage retain solar heat.

Yavapai College

Simple Duct Solution The ICF foundation simplifies the inclusion of sealed ducts (and mechanical equipment) in conditioned space. All ductwork is located in the unvented, conditioned crawlspace, and sealed with mastic. Register boots are sealed to the wood floor with silicone caulking. Third-party duct leakage testing demonstrates that the duct sealing measures are effective. Duct leakage for this home is less than half the duct leakage allowable for meeting the local green building program standards.

Using Local Resources

Yavapai wall and roof sections details.

A 4x10-foot rooftop flat plate solar collector is expected to provide nearly all of the hot water needed for a family of four year round. In this home, it is anticipated that back-up electric water heating will be needed only after three contiguous days of deep cloud cover (a rare occurrence in this climate of over 330 days of sunshine each year). The system is “very effective,” according to Grahame, who has been installing these systems for five years, “The homeowner doesn’t know what’s generating the hot water. A state rebate of $700 for the system improves the economics.”

“Light” on Energy Use The lighting package includes 12 permanent (pin-type) fluorescent fixtures, 14 standard fixtures fitted with screw-in compact fluorescent bulbs, and a tubular skylight in the master bedroom closet and the laundry room. According to Grahame, the fluorescent bulbs are expensive, running about $500 for a 2,000 s.f. house, but the fixture price is about the same as conventional. He recommends buying “natural spectrum” light bulbs for the best light and says that ENERGY STAR®-labeled light fixtures and bulbs are readily available at building supply stores.

A Sales Commission In commercial construction, the process of commissioning—the systematic testing of each mechanical system to ensure proper design, installation, and performance—is standard. Yet, the commissioning process is only beginning to take hold in the residential construction industry. By following a strict commissioning process for each home they design and build, Yavapai College students know that their homes perform exceptionally well. The first step in the process is a duct blaster test before drywall. “This is a very important step,” says Grahame, “because leaks in ducts or

Yavapai College

mechanical equipment can be sealed [at this stage].” After construction, a blower door test checks for overall air leakage. The tests are part of the learning process for Grahame and his students. “We’ve been testing for eight years. It has helped us learn where the potential for air leakage exists. We’re constantly tweaking it to obtain better results.” Some areas that have proved leaky in the past have been recessed can lighting, fireplaces, window openings, and any penetrations to the exterior.

Where to Start For builders starting out with energy efficiency, Grahame recommends taking a class to learn the fundamentals of building science. He suggests reading the Energy and Environmental Building Association’s Builders’ Guide for your specific climate, looking at available community college courses, or attending local builder’s events. He also recommends the extensive resources available in publications and through the Internet.

Sorting it Out As a training institution, Yavapai is always fine-tuning its house designs. “By no means are our homes perfect,” Grahame says. “We are always seeking ways to improve.” To keep up with the latest building science information, Grahame attends workshops and conferences and reads a number of home building journals such as Environmental Building News, Energy Design Update, SolPlan Review, and Home Energy. “I teach my students to question everything. Just because it’s new, doesn’t mean it works. First we get proof, and then we try it.” For future houses, Grahame is planning to streamline the duct system by delivering air to room interiors and by using central returns, jumper ducts, and transfer grilles.” Our thermal envelope is so good now, we don’t need to run ducts to exterior walls like we’ve done in the past.” In addition, although students used the Energy-10 and REM/Rate energy analysis software programs to predict energy cost, savings, and consumption for this home, Grahame intends to bring software modeling into the design process for future homes as part of the architectural curriculum.

Yavapai College

Pardee Homes

Pardee Homes San Diego, California Custom/Demonstration Home – Mixed-Dry Climate

s a multi-regional al builder/developer, Pardee Homes is competing with much larger national companies in all of its markets. Since 1998, energy efficiency has helped secure the Pardee brand as forward-thinking. Pardee’s project, Soleil at Bordeaux, showcases Pardee’s commitment to the environment with highly-efficient homes that also produce power from the sun.

Setting their Sites on the Sun To plan for incorporating a roof-integrated photovoltaic (PV) shingle product into Soleil at Bordeaux homes, Pardee Homes worked closely with manufacturer GE Energy to produce a solar site design for the entire community. Using the architect’s roof designs, Pardee and GE Energy selected the most appropriate roof design for each lot to maximize the use of solar while minimizing shading from architectural features such as chimneys and dormers. GE Energy, in turn, provided precise system layouts for each roof plan. According to Joyce Mason, vice president of marketing for Pardee Homes, “There is no substitute for taking the time to do [detailed PV system siting]. There are no shortcuts. You need to analyze each lot, look at each house, and put the best house on the lot to give you the best solar orientation.” In addition, Mason advises integrating solar roofing into the architectural design process at the very beginning. “The whole point of a roof-integrated system is design,” she says. “Pardee tries to show that you can have energy efficiency with good design.”

Pardee Homes

Snapshot of Energy Features Foundation: Slab-on-grade Wall Construction: 2x4 at 16 inches-on-center Wall Insulation: R-13 fiberglass batts with 1” exterior rigid foam taped at seams for insulation and air infiltration barrier Ceiling/Roof Construction: Trusses Ceiling/Roof Insulation: R-30 blown cellulose Windows: Low-E, tinted; U-0.34; SHGC 0.31 Air Sealing: Caulking and sealing protocols followed Blower Door Test: 3.3 ACH50 Heating Equipment: 92 AFUE gas furnace with programmable thermostat Cooling Equipment: 14 SEER air conditioner Ducts: None in conditioned space Duct Losses: 78 cfm to exterior at 25 Pascals Ventilation: Spot exhaust ventilation Hot Water System: 82 percent efficient tankless gas water heater Solar Hot Water: None Solar PV System: 2.4 kW trellis-mounted system Lighting: 100 percent fluorescent lighting—30 permanent (pin-type) fluorescent fixtures and 31 CFLs in conventional fixtures Appliances: ENERGY STAR refrigerator (584 kWh/yr), washer (351 kWh/yr), and dishwasher (361 kWh/yr) HERS Score: 90.0 (HERS rating system doesn’t yet credit PV system or fluorescent lighting) Construction Cost: $66 per s.f.

Scoping the Work “You need to look at reducing a home’s energy demand before considering producing on-site power,” says Mason. On the efficiency side, Pardee works with energy consultant ConSol to perform computer simulations that help specify windows, insulation, and equipment for the impact of each on energy consumption and first cost. Pardee works with ConSol to comply with ComfortWise—a program that certifies homes meeting California’s ENERGY STAR® standards. As part of the ComfortWise process, ConSol performs computer modeling to size HVAC loads, ducts, and equipment according to the industry-recognized standards such as ACCA Manual J, D, and S (see Resources). The program also sets protocols for caulking and sealing; window, door, insulation, and PV system installation; and HVAC system design and installation. The protocols, required to receive a ComfortWise designation, simplify the process of creating scopes of work for subcontractors. ComfortWise protocols are available through the ComfortWise website (see Resources).

Inspections

Where the lot or roofline isn’t suitable for solar orientation, some homes in the development have PV systems on a backyard trellis.

During construction, ConSol performs regular inspections to ensure that systems are installed according to specifications. Inspections at rough-in document the quality of insulation installation, caulking and sealing, and duct installation. At the final inspection, several tests are conducted: airflow through supply and return registers is measured with a flow hood and results are compared with Manual J calculated air flow rates; a blower door test measures air infiltration; and a duct blaster test checks for duct leakage. The inspections and tests are used to produce a Home Energy Rating Score (HERS).

Lovely Lighting Pardee’s impressive HERS of 90 doesn’t even account for two energy-saving features – the PV system and the all-fluorescent lighting package. According to Mason, customers can’t tell the difference in the lighting, but Pardee can tell the difference in the model home’s electric bills. “Homebuyers get nervous about fluorescent lighting, but we show that it can be lovely. All the feedback has been positive. People are surprised, most of the time Pardee’s model home features allfluorescent lighting.

Pardee Homes

they don’t know its fluorescent,” says Mason.

Using the Climate to your Advantage According to Mason, it is sometimes necessary to compromise a little on efficiency for the sake of practicality. For example, the original architect’s design didn’t lend itself to placing ducts in conditioned space and, based on the builder’s experience, the practice wouldn’t have provided a lot of energy value due to the mild climate. “Located only A site analysis determines suitability of house orientation for solar power systems. five miles from the ocean,” says Mason, “the home doesn’t experience temperature extremes. A lot of times you can open the windows and cool LOT PLAN ELEV REV SIDE POWER PANELS SQ FT NOTE the house down, there is a nice coastal 96 3 A 1.2kW 12 Trellis Option 97 1 C R R 2kW 40 200 Option breeze.” Although the company puts ducts in conditioned space in other areas, it couldn’t justify the cost on this home. There isn’t a big cooling load, says Mason, “Sometimes people forget that you can get good ventilation in a moderate climate. When looking at energy efficiency, you need to use the climate to your advantage.”

Starting Out “The best place for a builder to start with energy-efficient construction,” says Mason, “is the ENERGY STAR program. It’s a welldefined program that has nice branding. When you build to ENERGY STAR standards, you build to higher standards.”

98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119

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48 12 48 40 12 40 12 40 48 48 12 48 40 12 12 40 48 12 40 48 40 12

250 Trellis 250 200 Trellis 200 Trellis 200 250 250 Trellis 250 255 Trellis Trellis 200 250 Trellis 200 250 200 Trellis

Standard N/A Standard Option Option Option Option Option Standard Standard Option Standard Option Option Option Option Standard Option Option Standard Option Option

The solar site analysis determined the most appropriate house plan and elevation and PV system location and size for each lot in the subdivision.

Mason recommends getting a good energy consultant so that you are designing appropriately for your climate from the start rather than waiting until construction has started. “After construction, she says, you are just trying to fix something that doesn’t work. In the long run, it’s less costly and more energy efficient.”

Pardee Homes

Thinking Ahead Pardee is constantly evaluating new technologies, although it admits to not always being the first to adopt new things. The latest technology the company is testing is a unique ventilation system that brings in outdoor air when the temperature outside is lower than indoors instead of operating the air conditioning system.

After helping to select the most appropriate roof design for each lot, the PV roofing product manufacturer provided precise system layouts for each lot.

Pardee Homes

Casa Verde Builders Austin, Texas Affordable Home – Hot-Humid Climate

he goal of Casa Verde Builders, a non-profit corporation, in conjunction with parent company American Youth Works, is to create affordable, energy-efficient homes for low-income homebuyers by using the construction process as a learning tool for local atrisk youth.

It All Adds Up Chester Steinhauser of American YouthWorks says, “For the kids—who are learning in an outdoor classroom, are paid a stipend, and gain practical skills—it’s a very positive experience. The students take a lot of pride in their work, realizing they are part of something big. The homes attract a lot of attention, host visitors from abroad, and have the opportunity to win awards such as the EVHA.” Steinhauser goes on to say, “Along the way, the kids learn a lot. There’s a lot of math, geometry, and economics that go into a house, and the subjects ‘come alive’ to the students who can see the concepts applied.”

Casa Verde Builders

Start Simple

Snapshot of Energy Features Foundation: Pier and beam Wall Construction: Wheat straw structural insulated panels Wall Insulation: R-21 (wheat straw in SIPs provides insulation) Ceiling/Roof Construction: Trusses Ceiling/Roof Insulation: R-30 cellulose Windows: Low-e; U-0.56; SHGC 0.36 Air Sealing: Window and door openings foam sealed; pre-drilled channels for wiring; no plumbing in exterior walls Blower Door Test: 6.15 ACH50 Heating Equipment: 80 AFUE gas furnace with programmable thermostat Cooling Equipment: 13 SEER air conditioner Ducts: All in conditioned space with furred-down central hallway plenum Duct Losses: 50 cfm total at 25 Pascals; no leakage to exterior Ventilation: Spot exhaust Hot Water System: Centrally located gas tank-type water heater Solar Hot Water: None Solar PV System: None Lighting: 2 permanent fluorescent fixtures; all standard fixtures fitted with screw-in compact fluorescent lightbulbs Appliances: None provided HERS Score: N/A Construction Cost: $50 per s.f. (not including labor)

As a non-profit builder, there is little money for Casa Verde to invest in high-tech energyefficiency “gadgets.” Instead, efficiency is achieved through thoughtful design and careful material selection. Steinhauser says, “For example, it doesn’t cost anything to turn the house on the lot to take advantage of solar gains for heating. Placing the kitchen, baths, and laundry in close proximity to each other cuts energy loss from hot water piping and reduces plumbing material and installation cost.” He adds that almost everything the company uses for energy and resource efficiency—from drywall clips to recycled carpets—is available at the local building supply store.

Steinhauser’s advice to hot-climate builders who want to start building energy-efficient homes is to look for low-cost measures that will have a big impact on energy consumption. A tactic he particularly likes is placing a huge porch on the southwest side of the house for shading. In addition to the practical energy aspects, a porch captivates, draws homeowners outside, and helps create a sense of community. An exterior ceiling fan helps cool the porch, further encouraging its use. While Steinhauser thinks photovoltaic systems and other high-tech items are terrific, he feels there are a lot of other measures that can net equal impact at a much lower cost.

Keep Your Cool For Austin’s hot climate, Casa Verde seeks ways to reduce the need for air conditioning. Looking at houses built before air conditioning was standard, the company notes that window shading and solar orientation, ceiling fans, and light-colored materials were commonly used.

Casa Verde’s youth workers help keep labor costs low.

Casa Verde Builders

Steinhauser adds that continuous ridge and soffit venting is a low-cost item, and increasing eave length for shading is relatively inexpensive. Where possible, bedrooms were placed at the corners of the building in order to improve natural airflow. Reflective roofing, which further reduces heat gain, adds cost upfront. However, the durability and energy benefits make the cost justifiable. To minimize HVAC equipment costs for the hot climate, the builder opts for a relatively low efficiency furnace and spends more on high efficiency air conditioning equipment.

Think Locally Steinhauser describes himself as lucky. When he needs help to determine if a product can be justified from an environmental or energyefficiency standpoint, he turns to the Austin Green Builder program—a program that is dedicated to helping builders find simple ways to make homes more energy efficient. Steinhauser says, “When a salesman comes to me with claims about a product, I don’t need to determine if a product is real. The [Austin Green Builder] program validates the research for me.” Casa Verde’s simple floor plan keeps construction costs Steinhauser points out that Austin’s program low. has helped create green builder programs in other states and that a home builder might ask their local energy office about starting a similar program. For more information about the program, visit the Austin Green Building website. For local Home Builder Associations desiring to start a local green builder program, the National Association of Home Builders (NAHB) offers an excellent resource, Model Green Home Building Guidelines, available for free from the NAHB website.

For passive solar design calculations, the company turns to Gayle Borst, a partner in the local architecture firm Stewardship, Inc., who determines the location of a home on a site and calculates eave length for shading. Although about 80 percent of Borst’s services are volunteer, Steinhauser encourages other builders to obtain similar design services. “It’s a pretty simple thing to do,” he says. “She can basically plug a few values into a software program and get the answers we need.” For guidelines on passive solar design, see the Sustainable Building Industry Council’s Passive Solar Design Strategies.

The use of porches encourages outdoor living to reduce cooling needs.

Casa Verde Builders

Innovative Materials

Ridge and soffits venting is one low-cost method that Casa Verde employs to reduce cooling needs.

Casa Verde’s unique position as an educational entity allows them some flexibility when it comes to materials selection. For example, the builder tried structural insulated panels (SIPs) in which wheat straw, rather than foam, provides insulation between two OSB panels. Although the wall materials cost about three times as much as insulated stick-framed walls, the company can justify the product because of its overall environmental benefit of using agricultural waste products and reducing the need for dimensional lumber. For conventional builders, labor savings for SIPs would make up some of the cost difference—a SIPs building can be erected in a day—but labor costs are generally not a factor for Casa Verde.

Ducts in Conditioned Space— Affordably

By furring down a central hallway to serve as an air plenum, the builder found an inexpensive method for keeping ducts in conditioned space.

Casa Verde understands the importance of tight ducts in conditioned space. However, they find that it can be expensive to keep ducts inside the building envelope. The company arrived at a unique solution where a central hallway with furred-down plenum serves most of the rooms in the house. In addition to being inexpensive, it proved to be an effective way to construct tight ductwork—leaking about five percent of air handler capacity at 25 Pascals.

Planning for the Future Screw-in compact fluorescent lamps (CFLs) were used throughout the interior and exterior of the home. Compared with incandescent bulbs, CFLs use less energy for the same light output, last longer, and add less waste heat to the house. By using CFLs that fit into standard lighting fixtures rather than permanent fluorescent fixtures (that accept 2- or 4-pin lamps), the company keeps lighting hardware costs low. Although money is saved through hardware costs with the screw-in CFLs, the company finds that, when buying replacement bulbs, homeowners almost universally opt for incandescent bulbs, which are less than onethird the cost of CFLs. Therefore, in future homes, the company will switch to pin-type permanent fluorescent fixtures. The lamps have a much lower replacement cost than screw-in CFLs and will provide homeowners with the most economical and efficient lighting package for the long run.

Casa Verde Builders

The Next Level Most of Casa Verde Builders’ buyers are first-time homeowners who have previously rented homes. Coming from the “utilities included” mentality, the builder faces challenges in getting homeowners to program thermostats and to get into the habit of shutting off lights when leaving a room. Nonetheless, results of energy monitoring from Casa Verde’s homes shows that the homes consume about 40 percent less energy than typical homes in Austin. Steinhauser says, “The true energy efficiency of a house relies on the habits of the homeowner.” The company tracks energy consumption of its homes through Austin Energy, the local utility, and finds that the same house plan on the same block can use double the amount of energy. “It’s all habits,” declares Steinhauser, “Who is leaving their lights on? Who is running the AC while they are gone? Who uses the programmable thermostats to set back temperatures?” For builders to have the greatest impact on household energy consumption, he feels there is a tremendous need to get homeowners’ participation. Although Casa Verde’s homeowner’s manual describes ways of living with less energy, most homeowners may never look at their manual.

Casa Verde Builders

Ferrier Builders

Ferrier Builders Ft. Worth, Texas Custom Home – Hot-Humid Climate

nergy efficiency is Ferrier Builders’ business. In fact, its corporate mission is “…to advance, communicate, and facilitate energy-efficient and sustainable building practices into the home building industry and into the homes and structures we build.” The company has been building energy-efficient homes since its inception in 1984 and continually seeks ways to improve.

From Soup to Nuts According to Ferrier Builders’ president, Don Ferrier, the company has evolved from one that concentrated on building an energy-efficient building shell to one that incorporates a building science “systems approach” to home building. According to the EVHA judges, the company “really understands the big picture.”

Design Decisions As a custom home builder, many decisions are driven by the customer. The process for selecting energy-efficiency features varies with each client. For this winning home, the owners did a tremendous amount of research. From the start, the owners wanted to incorporate energy efficiency into the home without distracting from the home’s appearance.

Ferrier Builders

Snapshot of Energy Features Foundation: Slab-on-grade Wall Construction: Structural insulated panels with exterior housewrap Wall Insulation: R-35 Ceiling/Roof Construction: Structural insulated panels Ceiling/Roof Insulation: R-29 Windows: Low-E, gas-filled; U-0.32; SHGC 0.32 Air Sealing: Sill sealer; Sealant at SIP joints; Penetrations foam sealed; Low-expanding foam around windows and doors; Casement windows for low infiltration; Floor joist construction detail eliminates rim joist; Caulking at joints between SIPs and floor and top and bottom plates Blower Door Test: 2.9 ACH50 Heating Equipment: Four zone, 9.5 HSPF heat pump with programmable thermostat Cooling Equipment: Four zone, 12 SEER heat pump Ducts: All within conditioned space and sealed with mastic Duct Losses: No leakage to exterior Ventilation: Designed for natural ventilation; No wholehouse mechanical ventilation Hot Water System: 0.88 EF tank-type electric water heater Solar Hot Water: None Solar PV System: None Lighting: 50 percent fluorescent fixtures, 25 percent incandescent fixtures fitted with CFLs Appliances: ENERGY STAR washer (209 kW/yr) and dishwasher (446 kWh/yr) HERS Score: 91.0 Construction Cost: $87 per s.f.

A secondary criterion was that energy features have a payback period of five years or less—with a longer payback period acceptable under certain circumstances. For example, although an energy simulation showed savings, the owner chose not to use a tankless water heater—opting instead for a lower-efficiency tank water heater. However, they chose a thermostatic shower valve, which was something they really wanted, even though the payback was significantly longer than the tankless water heater.

It Takes a Village For many of its fully custom homes, Ferrier Builders designs the homes along with the owners. If an architect or engineer is to be involved, Ferrier makes sure that that person is involved from the start. In order to build the best energy-efficient home possible, Ferrier feels it is necessary to form a design team. He finds that most people that want a very energy-efficient custom home are willing to make this effort.

Taking Advantage of Nature’s Bounty

As the EVHA judges noted, Ferrier Builders “didn’t just place a bunch of energy-efficient building components into a house … they first came up with a design that responded well to its site.” Extensive consideration was given to the effect of the sun on energy use. To minimize the home’s exposure to the harsh Texas sun, the home is oriented so that its shortest sides face east and west—where solar control is difficult because the rising and setting sun can shine directly into windows. A garage on the west side further reduces exposure to the low-lying sun on hot summer days.

South-facing porch roof will block most solar gain, even desirable winter gains, but was very important to the homeowner.

Ferrier Builders

Overhangs on the south side were sized to provide shading during the warmer seasons when the sun is high in the sky, and to allow solar heat gain when the winter sun is lower. However, aesthetics occasionally overruled efficiency. For example, the

south-facing porch roof will prevent most solar gain throughout the year— but the homeowner’s desire for the porch was deemed more important. The house is, in essence, only one room deep to facilitate crossventilation. Two stairwells on opposite ends of the home act as thermal chimneys—with the open floor plan allowing hot air to flow up the stairwells and out the high operable windows.

Trotting through the Dog Days of Summer A dog trot house design—in which a central passageway connects two houses or living areas—is common among North Texas cabins built by early settlers. By employing a passive ventilation strategy to take advantage of prevailing winds, a dog trot house successfully provides cool shaded space in the South’s hot, humid climate. This home’s dining area was designed to act like a dog trot to create natural air circulation. Exterior photo of dining area which acts like a dog

According to Mississippi State University trot, encouraging natural breezes when the doors researchers, a dog trot house design is extremely are open. successful in creating ventilation for passive cooling. As wind passes over the tall roof, the pressure is much higher on one side of the building than the other. This pressure differential forces air to move through the central passageway at substantially greater speeds than the wind at the exterior of the house.

Concrete Details On the first floor, stained concrete floors (and limestone walls in the dining area) absorb solar heat in the winter. The heat is slowly released and warmed air can be delivered to the living area by opening the connecting door. The dining area also serves as an airlock entry in the winter. The homeowners enter the house from the garage into the sunroom. Another door separates the sunroom from kitchen—thereby preventing a cold gust of air from entering the house directly.

The SIPs Have It

Interior of dining area showing stained concrete floor that absorbs and slowly releases solar heat.

Ferrier Builders constructs nearly all its homes with structural insulated panels (SIPs). When they first started using SIPs in 1985, it only took a couple of homes before the framer— who was versatile and willing to try new things—became proficient with the system. “By the third house, it was basically the same,” says Ferrier. The system costs more, he adds, but it “gives us the most ‘bang for our buck.’”

Ferrier Builders

Although another wall system could be built to be as energy efficient as a SIPs wall, Ferrier says, “The structure, insulation, and sheathing go up in one step [with SIPs]. You have to go about 10 extra steps to get [stick-framed walls] to the same level of efficiency. By the time you do that, there might not be an additional cost.”

Zipping SIPs Through 20 years of experience building with SIPs, the builder has developed an airtight plan for ensuring tight construction. SIPs wall and roof panels under construction.

Gasketing material is placed between the slab and sill plate to prevent air infiltration. Sealant is applied to all joints in the SIP walls and roof before the panels are abutted and fastened. After installation, all voids are sealed with expanding foam. To avoid air infiltration and poor insulation at the band joist, the builder uses a joist hanger to support the second-story floor system rather than placing floor trusses on top of the SIP walls. The joint between the first and second floor SIP is sealed, and the top and bottom edges of the subfloor are sealed to the adjacent SIP wall. All penetrations (electrical, mechanical, plumbing stacks, etc.) are sealed with expanding foam. To further tighten the building shell, casement windows—which have a compression seal that minimizes air infiltration through the window units—are used. Low expansion foam is around all windows and doors.

Detail of revised SIP wall to second story floor truss connection that provides continuous SIP insulation.

Easy Ducts It The SIPs wall and roof construction makes it easy to bring ductwork into conditioned space—since the entire house volume, including the attic area, is conditioned. Ducts were sealed with mastic to prevent leakage and to ensure that airflow is delivered to each room as designed.

Keeping the Cool (and Heat)

Detail of the original SIP wall to floor truss connection that was revised to improve exterior wall insulation.

Ferrier Builders

The HVAC layout was carefully planned to minimize the length of refrigerant lines, keep the air handler and duct work in conditioned space, and to locate the compressors in shaded areas. In hot and humid climate of Texas, an energy recovery ventilator, which can dehumidify incoming air in the summer, is sometimes used. However, heat recovery ventilators don’t make sense for the climate—they bring in too much humidity during the long cooling season. For this house, no additional

mechanical ventilation was added because the homeowners like to open windows and doors as much as possible and because the unique house design encourages natural airflow. Programmable thermostats operate four heating and cooling zones. Since each zone has different passive solar heating and cooling properties, the four-zone control offers comfort throughout the home. The upstairs zone can be shut off when the kids are away at college and the dining area is a separate zoneâ&#x20AC;&#x201D;which is almost always turned off. Because of the air movement through the dining area (the dog trot area), the owners only need to cool the room for about one month of the year.

Energy-Saving Appliances A top-of-the-line front loading washer helps conserve hot water energyâ&#x20AC;&#x201D; using only one-third the energy of a conventional washer. A matching dryer uses a lower-temperature drying cycle and a highly accurate humidity sensor to reduce drying energy needs. A pair of drawer-type dishwashers allows the homeowners to run smaller loads, or to run both when more capacity is needed.

Bringing It All Together The best intentions donâ&#x20AC;&#x2122;t always translate to the best-performing house. Therefore, Ferrier Builders has a stringent daily jobsite inspection to ensure that homes are built as specified. In its long history of building with SIPs, Ferrier has established relationships with contractors who understand the importance of energy efficiency to the company and the importance of installation to the proper operation of the home. When framing begins, the builder arranges a meeting between the framing, HVAC, plumbing, and electrical (and sometimes roofing) contractors to coordinate details. To keep abreast of building science issues, the builder and the construction superintendent attend Energy and Environmental Building Association (EEBA) and local HBA seminars and read the latest building science publications.

Model Energy Performance Ferrier Builders partners with Guaranteed Watt Saver Systems (GWSSI), a firm that helps builders design and test homes for energy efficiency to analyze various design decisions using the software program REM/Rate. The program provides a Home Energy Rating Score (HERS) based on predicted heating, cooling, and water heating energy use. The final home design resulted in a HERS of 91, which surpasses the International Energy Conservation Code (IECC) by 30 percent and will save 13 tons of CO2 each year over a home that simply meets the IECC.

Ferrier Builders

Use What You’ve Got According to Don Ferrier, the EVHA application “was a chore to complete but was well worth the effort as it helped us evaluate our approach.” For builders wanting to build more efficiently, Ferrier advises to “start with the proper orientation—anyone can do this with any home.” In the hot Texas climate, this translates to avoiding windows on the east and west sides of the home, placing glass primarily on the south side and making sure it’s shaded. “If you have a view, you can use windows to take advantage of it, but make sure the windows are shaded,” he adds. Next, Ferrier advises builders to build a high-quality envelope. “I choose SIPs, but you can use other systems as long as you have a high quality installation and control air infiltration.” Ferrier’s last piece of advice is to get the HVAC equipment and ducts inside conditioned space. Ferrier acknowledges that this is more difficult to achieve in a production home, but he says, it can be done. “The greenest thing you can do in home building is save energy”, Ferrier contends. “If you do the simple things, the owner saves money every month. It’s to the owner’s benefit. They’ve saved in energy what they’ve spent in mortgage. And they are more comfortable.”

Ferrier Builders

John Wesley Miller Companies Tucson, Arizona Production Home – Hot-Dry Climate

or the 2005 EVHA Builder of the Year, energy efficiency is at the core of John Wesley Miller Companies’ business: “Our mission is to design and build the most energyefficient development in the world by incorporating the latest energy saving technologies … in all of the homes we build.” The Armory Park del Sol development in downtown Tucson combines desert climate-appropriate design with rooftop solar energy production to do just that.

A Solar Community Develops As a builder/developer, John Wesley Miller Companies (JWM) arranged the lots in the Armory Park del Sol subdivision so that each home can have optimal orientation for a solar PV and hot water system. The covenants, codes, and restrictions for the development govern the placement and maximum height of trees to avoid shading on the rooftop solar systems. Desert-style parapet walls are ideal for placing the solar hot water and PV panels out of sight. Companies that do not develop land, but that would like to employ solar energy on homes, can try talking to developers about laying out future developments to optimize the use of solar energy.

John Wesley Miller Companies

Snapshot of Energy Features Foundation: Engineered slab on grade; R-12 slab edge insulation Wall Construction: 8-inch solid-grout CMU Wall Insulation: R-12 exterior rigid foam Ceiling/Roof Construction: I-joists/flat roof Ceiling/Roof Insulation: R-38 fiberglass batt insulation Windows: Low-E, gas-filled; U-0.32; SHGC 0.30 Air Sealing: Foam around rough openings of windows and doors Blower Door Test: 2.9 ACH50 Heating Equipment: HPSF 8.6 heat pump with programmable thermostat Cooling Equipment: 12 SEER heat pump Ducts: 100 percent conditioned space; R-6 insulation Duct Losses: 15 cfm total at 25 Pascals Ventilation: Passive inlet to return side of air handler Hot Water System: Solar hot water with tankless backup Solar Hot Water: Batch-type solar water heating system Solar PV System: 1.5-kW grid-connected photovoltaic system Lighting: Combination incandescent and fluorescent Appliances: ENERGY STAR refrigerator (643 kWh/yr) and dishwasher (449 kWh/yr) HERS Score: 91.8 Construction Cost: $148 per s.f.

Each home in Armory Park del Sol subdivision features a solar electric and solar hot water system. John Wesley Miller Companies has the advantage of working with a progressive utility company, Tucson Electric Power (TEP), that is aggressively encouraging the installation of renewable energy power systems. Currently, the rebate for solar systems is $3 per installed watt. Therefore, all new homes in Armory Park del Sol are getting a $4,500 rebate from the power company, in addition to lower energy bills, for their 1.5-kW photovoltaic system. The State of Arizona, in turn, provides a $1,000 tax credit for solar water heating and solar electric systems.

The Bottom Line

Not only are homeowners saving on energy bills by producing power onsite, but efficiency features make the cost of heating and cooling very low. According to an independent study, the utilities for an average home in the Armory Park del Sol subdivision run about half of what a typical new home in the city costs. Through a synergistic partnership with TEP, the EVHA winning home’s heating and cooling bills are guaranteed, for five years, not to exceed $0.76 per day on an annual basis. Under the TEP program, periodic quality inspections are performed—at the framing, insulation, and HVAC phases—plus a final inspection. And everyone benefits—the builder can be assured that the house was constructed as designed; TEP adds a new house to its customer base that sends power to the utility grid at times when TEP needs it most; and the customer’s utility bills are guaranteed to fall below a certain amount each month. Inspections include performance testing to check whole-house air leakage, duct leakage, and pressure in each room with the doors closed. Reducing the pressure difference across interior doorways facilitates air circulation to all rooms and results in a more comfortable home.

Solid Construction Lots in the Armory Park del Sol subdivision are oriented for access to solar energy.

John Wesley Miller Companies

In the Tucson climate, Miller feels masonry construction adds a lot of value to the company’s homes. JWM Companies’ wall system, which consists of CMUs with solid grout, R-12 exterior rigid foam, and interior steel-framed walls, produces a tight house (2.9 ACH50) with little additional air sealing required except at rough openings around windows

and doors. Because plumbing and electrical lines run through the interior steel-framed walls, and all ducts are in the conditioned space, no additional air sealing is needed for mechanical penetrations. Solid concrete construction provides a lot of thermal mass to temper the extreme heat and cold of the desert climate. The thermal mass properties, Miller explains, of solid-grout concrete block combined with exterior insulation helps temper the indoor environment from the often extreme outdoor conditions. In addition, people are willing to pay for the quality of the company’s masonry construction, “The resale value is much higher for masonry,” Miller says.

A 1.5-kW photovoltaic system takes advantage of abundant solar energy to produce electricity which turns the meter backwards.

Selective about Windows Spectrally-selective coatings on the windows offer protection from the brutal Tucson heat and sun. Having a low U-value of 0.32 prevents conduction of heat indoors and heat loss during the cool nights, but more importantly, the low SHGC of 0.30 helps mitigate direct solar heat gain during the summer months.

Engineering the HVAC System

A batch-type solar water heater collects and stores hot water produced by the sun.

As part of the design team, a local professional engineer does an analysis on all plans for proper sizing of HVAC equipment and location of ductwork. Miller relies on the engineer, who he describes as a “practical guy who grew up in the tin-bending business.” The high ceilings and architectural features, combined with a knowledgeable HVAC engineer, allow the company to bring all ductwork into conditioned space. The ducts are enclosed in soffits below the insulation along the central core of the house plan. All ducts are sealed with mastic and tested for leakage. A central return and transfer grilles across interior doorways help equalize pressure throughout the house.

Building with the Climate For builders in a sunny desert climate looking to improve energy efficiency, Miller feels that, at a minimum, builders should install a solar hot water system. Next, he ecommends looking at better windows with low U-factors and low solar heat gain coefficients. He suggests that builders look at the value of thermal mass storage with masonry walls and exterior insulation. Finally, he says everyone should be insulating concrete slab foundations because “a tremendous amount of heat goes out through the slab in the winter.”

Hardware in the garage tracks solar electrical production.

John Wesley Miller Companies

Exploring and Experimenting JWM Companies is constantly seeking new and interesting building techniques and materials. Consideration is given, of course, to costs of new features—there must be a perceived benefit to the homeowner. However, according to Miller, cost isn’t always the only consideration.

A heating and cooling cost guarantee lets homeowners know the true cost of homeownership.

“A lot of what we do is trying something to see if it works instead of adopting only what is proven” he says. We don’t always look at the cost-benefit analysis. I like to explore and experiment and try things to see what happens. It’s research and it’s fun.” In addition, practicality often factors into a decision to use a new product—products must be available locally and must fit neatly into the construction schedule.

To this end, JWM Companies relies heavily on the subcontractors with which it has loyal and longstanding relationships. The company works closely with the trade contractors to determine the best materials, production, and processes to minimize energy use and take advantage of the abundant solar resource. Periodic meetings with staff and trades are held to review building practices, identify problems, and implement solutions.

Builders as Environmentalists As Miller eloquently sees it, “Builders are the environmentalists because we construct the built Shaded windows with low solar heat gain environment. We have the opportunity to improve that built properties mitigate the relentless heat of the environment every day and every year, to provide a higher desert sun. quality of life. We are the ones that can raise the bar to which all of us strive. That’s what we, as builders, can do to improve people’s quality of life.”

John Wesley Miller Companies

RESOURCES General Energy Efficiency Information Building America document database http://www.eere.energy.gov/buildings/building_america/pdfs/db/doc_db_bibliography.pdf NAHB’s Model Green Home Builder Guidelines Voluntary guidelines designed to facilitate the adoption of green home building practices and the formation of local green builder programs http://www.nahb.org/gbg U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Website that covers various aspects of building energy-efficient new homes http://www.eere.energy.gov/buildings/info/homes/newconstruction.html

Climate Information Building America climate region listing by county http://www.eere.energy.gov/buildings/building_america/pdfs/climate_regions_us_county_rev02.pdf Building America climate zone by map http://www.eere.energy.gov/buildings/building_america/cfm/project_locations.cfm Building America climate zone definitions http://www.eere.energy.gov/buildings/building_america/climate_zones.html

Database of Home Energy Raters http://www.energystar.gov Æ find local home builders Æ select “home energy rater” checkbox and your state in the drop-down menu

Training, Educational Seminars, Conferences, and Courses Advanced Energy Builder’s Series—Building High Performance Homes Helps the building industry produce better products while increasing profits and avoiding callbacks http://www.advancedenergy.org/buildings/courses/index.html Affordable Comfort Annual conference featuring educational session on building science http://www.affordablecomfort.org Energy & Environmental Building Association (EEBA) Houses that Work Seminars Educational outreach program based on principles of building science and the “system's approach” to construction for improved building performance and durability http://www.eeba.org/housesthatwork/default.htm

Resources

Energy & Environmental Building Association (EEBA) Annual Conference http://www.eeba.org/conference/ Florida Solar Energy Center Energy-efficient Florida Home Building Design and construction decisions for creating new energy-efficient Florida homes by combining the knowledge and resources of industry leaders with the U.S. Department of Energy’s technical capabilities. http://www.fsec.ucf.edu/ed/contin_ed/efficient.php International Builders’ Show (various sessions), The largest annual light construction show in the world that includes educational sessions on green building, energy-efficiency, and marketing. http://www.buildersshow.com Local utility and state conference (check with your State Energy Office or local utility company) National Green Builder’s Conference (various sessions), Annual conference aimed to assist builders in finding out cost-effective business decisions that also help the environment http://www.nahb.org/greenbuilding

Whole House Building America Program A private/public partnership that, by combining the knowledge and resources of industry leaders with the U.S. Department of Energy’s technical capabilities, develops energy solutions for new and existing homes. http://www.eere.energy.gov/buildings/building_america/

Foundations Construction details for conditioned crawlspaces http://www.buildingscience.com/resources/foundations/conditioned_crawl.pdf Crawlspace Insulation (2000). Four-page fact sheet that contains information on how to manage moisture in the crawlspace, insulate crawlspace walls, insulate under flooring, handle ventilation, and manage radon http://www.nrel.gov/docs/fy01osti/29238.pdf EEBA Guidebooks (series of guidebooks which recommend foundation construction details for each climate zone) http://www.eeba.org “How to Construct Unventilated Crawlspaces to Meet the Provisions of the 2003 International Energy Conservation Code (IECC) and 2003 International Residential Code (IRC)” Presentation available at http://www.energycodes.gov/news/broadcasts/presentations/webcast_04_crawlspaces.ppt Slab Insulation (2000). This fact sheet for homeowners and contractors discusses how to insulate slab-on-grade floors and control moisture, air leakage, termites, and radon http://www.nrel.gov/docs/fy01osti/29237.pdf

Walls Framing and Insulation Website containing descriptions of advanced framing techniques http://www.toolbase.org/tertiaryT.asp?TrackID=&CategoryID=70&DocumentID=2021

Resources

Advanced Wall Framing (2000). Six-page U.S. DOE fact sheet that describes advanced framing techniques, and design considerations http://www.nrel.gov/docs/fy01osti/26449.pdf EEBA Guidebooks (series of guidebooks which recommend wall construction details for each climate zone) http://www.eeba.org Website showing advanced framing construction details http://www.buildingscience.com/housesthatwork/advancedframing/default.htm. Yost, P. and A. Edminster, Optimizing Wood Framing, Building Safety Journal May 2003 Article on advanced framing that dispels common myths http://www.buildingscience.com/resources/articles/optimizing_wood_framing.pdf

Insulation Wall Insulation (2000). Four-page U.S. DOE fact sheet for homeowners and contractors on how to provide moisture control and insulation in wall systems http://www.nrel.gov/docs/fy01osti/26451.pdf

House Wrap EEBA Guidebooks (series of guidebooks which recommend wall construction details, including weather barrier details, for each climate zone) http://www.eeba.org Weather-Resistive Barriers (2000). Four-page fact sheet for homeowners and contractors on how to select housewrap and other types of weather-resistive barriers http://www.nrel.gov/docs/fy01osti/28600.pdf

Rainscreen Approach to Siding Installation Fact sheet by the NAHB Research Center describing the approach, and providing some construction details http://www.toolbase.org/tertiaryT.asp?TrackID=&CategoryID=1555&DocumentID=2140

Air Sealing Advanced Air Sealing. Online manual (also available in printed format for a nominal fee) http://oikos.com/library/airsealing/ Airtight Drywall Approach (2002). Two-page fact sheet provided by the Southface Energy Institute which includes construction drawings http://www.southface.org/web/resources&services/publications/factsheets/24ada_drywal.pdf Airtight Drywall Approach (2003). Brief U.S. DOE fact sheet on the approach. No construction details are shown http://www.eere.energy.gov/consumerinfo/factsheets/bd8.html Air Sealing (2000). Four-page fact sheet on sealing air leaks to save energy in your home. http://www.nrel.gov/docs/fy00osti/26446.pdf

Ceilings and Attics Ceilings and Attics (2000). Four-page U.S. DOE fact sheet about installing insulation and providing ventilation through ceilings and attics. Includes construction details for efficiency and ventilation http://www.nrel.gov/docs/fy00osti/26450.pdf

Resources

EEBA Guidebooks (construction details by climate) http://www.eeba.org

Passive Solar Design Michael Crosbie, 1997, The Passive Solar Design and Construction Handbook (textbook), John Wiley & Sons.

Passive Solar Design (2000). Four-page fact sheet that discusses how passive solar design features can increase energyefficiency and comfort http://www.nrel.gov/docs/fy01osti/29236.pdf Sustainable Building Industries Council, Passive Solar Design Strategiesâ&#x20AC;&#x201D;Guidelines for Home Building, available from www.sbicouncil.org

HVAC System Advanced Space Conditioning, 36-page document describing the process of designing HVAC system for high-performance homes http://www.buildingscience.com/resources/mechanical/advanced_space_conditioning.pdf

Load Calculation ACCA Manual J. This manual from the Air Conditioning Contractors Association defines the procedure for calculating residential heating and cooling loads - www.acca.org Rudd, Armin, Design Process for Sizing: Cooling and Heating System Capacity, Room Air Flows, Trunk and Run Out Ducts, and Transfer Air Ducts (2003). Paper which describes the design process for load calculations and airflow calculations using ACCAâ&#x20AC;&#x2122;s Manual J with parameters to handle infiltration, ventilation, glazing, and airflow velocities for ducts http://www.buildingscience.com/resources/mechanical/509a3_cooling_system_sizing_pro.pdf

Duct Design ACCA Manual D. Available This manual from the Air Conditioning Contractors of America defines a procedure for designing residential duct systems - http://www.acca.org Air Distribution System Design (2003). Six-page U.S. DOE fact sheet which discusses options and offers design recommendations for residential duct systems http://www.eere.energy.gov/buildings/info/documents/pdfs/air_dist_sys_design-0782.pdf Better Duct Systems for Home Heating and Cooling, 12-page fact sheet from the Building America program which discusses how to design and create an efficient duct system, duct testing, and repair. http://www.eere.energy.gov/buildings/building_america/pdfs/30506_better_ducts.pdf Hawthorne, W., and S. Reilly, 2000, The Impact of Glazing Selection on Residential Duct Design and Comfort, Proceedings of the 2000 Winter Meeting, American Society of Heating and Refrigeration Engineers, v. 106, pt. 1. Dallas, Texas.

Transfer Grilles Discussion of the Use of Transfer Grilles to Facilitate Return Airflow in Central Return Systems Fact sheet from Building Science Corporation discusses transfer grille sizing and includes a brief list of grilles/registers that can serve as transfer grilles http://www.buildingscience.com/resources/mechanical/transfer_grills.htm

Resources

Transfer Grille Construction Details (from Building Science Corporation) http://www.buildingscience.com/resources/mechanical/transfer_grills2.htm

Heating and Cooling Equipment A list of energy-efficient equipment http://www.energystar.gov Æ look under “products.” Equipment Sizing—ACCA Manual S http://www.acca.org

Heating and Cooling Equipment Selection (2002). The fact sheet helps designers and builders choose heating and cooling equipment that will reduce initial costs, increase homeowner comfort, increase operating efficiency, and greatly reduce utility costs http://www.nrel.gov/docs/fy02osti/26459.pdf Rudd, Armin, Refrigeration System Installation and Startup Procedures, and Air Conditioning Equipment Efficiency (2003), Three-page fact sheet outlining the procedure for cooling system installation, startup, and equipment efficiency http://www.buildingscience.com/resources/mechanical/air_conditioning_equipment_efficiency.pdf

Heat Recovery Ventilation Common Questions about Heat and Energy Recovery Ventilators, fact sheet from the University of Minnesota Extension Service http://www.extension.umn.edu/distribution/housingandclothing/DK7284.html. The Home Ventilating Institute, Manufacturer’s association that certifies products and provides recommendations http://www.hvi.org/

Windows Efficient Windows Collaborative Provides recommendations for window properties by climate and includes information and fact sheets about window properties and technologies http://www.efficientwindows.org ®

ENERGY STAR -labeled windows ® Find windows bearing the ENERGY STAR label for your climate http://www.energystar.gov National Fenestration Rating Council, labels windows for U-value and SHGC Database of window products http://www.nfrc.org. Selecting Windows for Energy Efficiency 16-page U.S. DOE fact sheet http://windows.lbl.gov/pub/selectingwindows/window.pdf

Energy Efficient Appliances ®

Criteria for meeting ENERGY STAR requirements and a listing of current appliances meeting those criteria at http://www.energystar.gov Æ look under “products.” Energy Efficient Appliances (2001).

Resources

This fact sheet for homeowners and contractors explains the energy savings potential of efficient appliances, how to purchase them, and how to maintain them http://www.nrel.gov/docs/fy01osti/26468.pdf

Energy Efficient Lighting Energy Efficient Lighting, U.S. DOE fact sheet http://www.eere.energy.gov/consumerinfo/pdfs/eelight.pdf ENERGY STAR labeled fixtures, Directory of labeled fixtures at http://www.energystar.gov Æ look under “products”

Retailers of Energy-Efficient Building Products Energy Federation Incorporated One-stop shopping for hundreds of resource conservation-related products http://www.efi.org Oikos Online directory of manufacturers and retailer of energy- and resource-efficient products http://www.oikos.com Positive Energy Conservation Product The Green Builder’s Catalog - http://www.positive-energy.com Shelter Companies Providing customers with products and services for energy-efficient, healthier homes http://www.sheltersupply.com

Directory of Manufacturers and Retailers of Energy- and Resource-Efficient Building Products Oikos Green Building Products from Oikos http://oikos.com/products/index.lasso Sustainable Building Sourcebook http://www.greenbuilder.com/sourcebook

Renewable Energy Systems National Renewable Energy Laboratory’s Clean Energy Basics Website. A primer on renewable energy including a section on clean energy for the home http://www.nrel.gov/clean_energy/ General photovoltaic systems information from the Sustainable Building Sourcebook (City of Austin Green Builder Program) http://www.greenbuilder.com/sourcebook/Photovoltaic.html Photovoltaics: Basic Design Principles and Components, U.S. DOE Fact Sheet that provides an overview of residential PV systems including determining if a site is appropriate for a PV system, system sizing, design considerations, and a resource list http://www.toolbase.org/tertiaryT.asp?TrackID=&CategoryID=1215&DocumentID=3209 On-line performance calculator for grid-connected PV systems http://rredc.nrel.gov/solar/calculators/PVWATTS/ Photovoltaic system reading list by the U.S. DOE http://www.eere.energy.gov/consumerinfo/reading_resources/vc8.html

Resources

Solar Hot Water and Space Heating & Cooling Discusses the basic types of solar water heating systems and collectors http://www.eere.energy.gov/RE/solar_hotwater.html Solar Water Heating, a primer on solar water heating systems from the U.S. DOE http://www.toolbase.org/tertiaryT.asp?TrackID=&DocumentID=3216&CategoryID=949

Builder Programs City of Austin Green Builder Program http://www.ci.austin.tx.us/greenbuilder/ ®

ENERGY STAR http://www.energystar.gov Environments for Living http://www.eflhome.gov Local Home Builders’ Association (to find your local HBA, go to http://www.nahb.org Æ contact us Æfind your local builders’ association) State energy office http://www.naseo.org/members/states.htm

Corporations Providing Energy Analysis, System Design Services, and General Information Advanced Energy http://www.advancedenergy.com (NC) Building Science Corporation http://www.buildingscience.com (MA) BuiltWright http://www.builtwrightinc.com (CO) Comfort Home http://www.comforthome.com (PA) ConSol http://www.consol.ws (CA) Davis Energy Group http://www.davisenergy.com (CA) Florida Solar Energy Center http://www.fsec.ucf.edu (FL) Guaranteed Watt Saver Systems, Inc. http://www.gwssi.com (OK) Home Energy Raters (may also provide design assistance) http://www.energystar.gov. Look under “new homesÆfind local home builders” and check the “Home Energy Raters” box for your state. IBACOS http://www.ibacos.com (PA)

Resources

Local or State Energy Office (see http://www.naseo.org/members/states.htm for a listing by state) Local Utility Company NAHB Research Center http://www.nahbrc.org (MD) NAHB http://www.nahb.org (DC) Vermont Energy Investment Corporation http://www.efficiencyvermont.org (VT)

Financial Incentives DSIRE database for information about incentives for renewable energy in your state http://www.dsireusa.org National Energy Efficiency and Affordability Project Residential energy-efficiency database that tracks state and utility-sponsored incentives for energyefficiency http://neaap.ncat.org/db/

Resources

GLOSSARY Air Changes per Hour (ACH)

Measurement of the air leakage rate of a building, specifically, the number of times each hour the total volume of air in a building is replaced by outdoor air. Typically expressed as a rate experienced under normal, atmospheric pressures or under some higher test pressure. (Test pressure is typically 50 Pascals and, at this pressure, test results are often reported in ACH50.)

Annual Fuel Utilization Efficiency (AFUE)

Seasonal efficiency of a gas-fired furnace or boiler. Takes into account cyclic operation. The higher the number, the more efficient the heating equipment. Furnaces range between 78 and 96+.

Backdrafting

Potentially hazardous condition in which the exhaust from combustion appliances does not properly exit the building. This can be due to a number of factors including a blocked flue or a pressure difference within the home.

Blower Door

A large fan placed in an exterior doorway to pressurize or depressurize a building to determine its air leakage rate expressed in air changes per hour or cubic feet per minute.

British Thermal Unit per Hour (Btuh)

The amount of energy needed to change the temperature of one pound of water by one degree Fahrenheit.

California Corner

An Optimum Value Engineering technique that uses two studs (instead of the usual three or four) to make an exterior corner. The result is better insulation and use of fewer resources, in addition to cost savings. Several variations are possible.

Coefficient of Performance (COP)

Measurement of the steady-state performance of electrically operated systems, including ground-source heat pumps. It is the ratio of useful-energy output to purchased-energy input. Can also refer to gas-fired systems.

Combination System

Heating system that uses the domestic water heater for both water and space heating. Hot water is typically piped to a heat exchanger (coil), where a fan blows air over the coil to produce heated air.

Compact Fluorescent Lamp:

Fluorescent light bulb having a screw-in base, which fits into a conventional light fixture.

Condensing Furnace or Boiler

Refers to high-efficiency systems that extract such a high percentage of the available energy from gas combustion that the water vapor in the burned gas (combustion products) condenses to liquid water before leaving the furnace.

Conditioned Space

Area within a house that is heated and/or cooled. Conditioned space is separated from unconditioned space by a thermal envelope.

Desuperheater

Device that takes waste heat extracted by heat pumps or air conditioners and uses it to heat domestic hot water.

Glossary

Energy-efficiency Mortgage (EEM)

EEMs recognize that the monthly energy bill savings from improved energy efficiency can more than offset the increased monthly mortgage cost attributed to energyefficiency upgrades. Some products allow a higher loan-toincome or debt-to-income ratio while other newer, more innovative products finance 100 percent of all cost-effective energy-efficiency upgrades in the mortgage, thereby eliminating any increased downpayment and requalification requirements.

Energy Efficiency Ratio (EER)

Instantaneous efficiency of air conditioners measured at standard test conditions. The amount of cooling provided per unit of electricity purchased. The higher the EER, the more efficient the air conditioner.

Energy Factor (EF)

Overall efficiency of a water heater. The amount of hot water produced per unit of gas or electricity purchased. The higher the energy factor, the more efficient the water heater.

ENERGY STAR速 Home

An ENERGY STAR Home is predicted to use 30 percent less energy than houses built to the Model Energy Code (MEC) while maintaining or improving indoor air quality. The ENERGY STAR Home Program is a program of the U.S. Environmental Protection Agency and the U.S. Department of Energy.

Envelope / Thermal or Building Envelope

The protective shell of a building that separates the inside environment from the outside environment; includes both an insulation layer and an air infiltration layer.

Flex-Duct

Flexible ductwork made with an inner liner, a layer of insulation, and an outer covering of plastic.

Frost-Protected Shallow Foundation (FPSF)

Foundation system in which foam insulation is placed around the perimeter of a foundation to reduce heat loss through the slab and/or below-grade walls, subsequently raising the frost depth of a building and allowing foundations to be as shallow as 16 inches below grade.

Geothermal System

A heat pump that uses the ground or water as a heat source or sink. Efficiency is improved over air source heat pumps as the temperature of the ground or water is more constant and moderate than that of the air. Geothermal systems can include equipment which also produces domestic hot water.

Heat Pump

Similar to an air conditioner but can operate in reverse to heat as well as cool. Transfers heat (usually from the air) from one location to another.

Heating Seasonal Performance Factor (HSPF)

Efficiency of a heat pump in the heating mode, taking cycling into account; the amount of heating provided per unit of electricity purchased. The higher the HSPF number, the more efficient the heat pump. Heat pumps range between 6.6 and 9.7 HSPF. The higher the HSPF, the more efficient the heat pump.

High Efficiency Particle Accumulator (HEPA)

An air filter that captures a high percentage of all particles, including very small particles not captured by other types of filters.

Home Energy Rating System (HERS)

A collection of programs throughout the country that assign energy ratings based on predicted energy use of the house. Ratings are either on a scale of 1 to 100 points or 1 to 5-plus stars. Most houses built today without any special attention to energy efficiency typically earn an 80-point or three-star rating.

Heat Recovery or Energy Recovery Ventilator (HRV/ERV)

Engineered venting systems that recover useful energy from exhaust air.

HVAC Zoning:

Creating several â&#x20AC;&#x153;zonesâ&#x20AC;? or areas throughout the house, which can be heated or cooled independently by separate thermostats, from one central unit. While HVAC zoning can be accomplished in forced-air systems by using electronically-controlled dampers, it is most easily implemented in hydronic distribution systems.

Insulating Concrete Form (ICF)

Concrete form-wall constructed of foam insulation that remains in place after the concrete cures.

Low-Emittance (Low-E) Windows

Windows with a thin, invisible, metallic coating on one or more glazing surfaces that reduces the radiation of heat from windows. Low-e glass has a thin, invisible coating that reduces the flow of radiant heat through windows. The most common coating reduces solar heat gain and increases resistance to radiant heat loss through windows.

Manual-J

Method developed by the Air Conditioning Contractors of America to size heating and cooling equipment.

Mass Effect

Describes the effect of a high-mass material on heating or cooling requirements. High mass materials such as concrete, used in floors and/or walls, can absorb and store significant amounts of heat, which is later released. In some climates (those with lots of sunshine, low humidity, and large daily temperature fluctuations), high-mass materials can mean a reduction in cooling and heating requirements by delaying the time at which the heat is released into the house.

Mastic

Strong, flexible material having a thick, creamy consistency when applied, that is used to seal ductwork. Also used to describe a type of ceramic tile adhesive.

Model Energy Code (MEC)

A building code that requires houses to meet certain energyefficiency-related minimums such as insulation levels or energy consumption. Like most building codes, it is adopted on either a state or local basis, if at all, and may be amended.

Optimum Value Engineering (OVE)

Sometimes referred to as Advanced Framing. OVE framing techniques use less lumber and therefore improve a structureâ&#x20AC;&#x2122;s level of insulation. Techniques include 24-inch on-center stud layout, single top plates, engineered header sizes, and special corner and wall intersection configurations.

Programmable Thermostat

An automatic thermostat for control of heating and cooling systems that can be set at varying temperatures throughout the day or week based on a schedule entered by the occupant. Often used to lower temperatures (during heating, raise during cooling) at night or while occupants are at work. Advanced controls may include humidity and/or a ventilation system.

R-Value

Measure of the resistance of a material to heat flow. The higher the number, the greater the resistance to heat flow.

Radiant Barrier

A material that reflects radiant heat, typically a foil-faced or foil-like material used in roof systems. Used properly in some climates, it can reduce cooling requirements but has no positive effect on heating requirements.

Glossary

Sealed Combustion Furnace

Furnaces or boilers that draw air for combustion from outside the home directly into the burner compartment and vent exhaust gases directly to the outside. The systems eliminate the possibility of backdrafting.

Seasonal Energy Efficiency Ratio (SEER)

The amount of cooling provided by a central air conditioner per unit of electricity purchased; SEER is tested over the entire cooling season, taking cycling into account. The higher the SEER number, the more efficient the air conditioner. SEER, in contrast to EER and COP, takes into account the efficiency losses resulting from system cycling.

Sizing

Calculation of the heat loss and heat gain for a building at “design temperatures” (those close to the maximum and minimum temperatures anticipated for a given location) in order to select heating and cooling equipment of sufficient capacity. Installing excess equipment capacity, or oversizing, is common but leads to inefficient operation and, for air conditioners, decreases the dehumidification. Calculations are most often done according to the ACCA Manual J (or similar) procedure.

Solar Heat Gain Coefficient (SHGC)

An indicator of the amount of solar radiation admitted through and absorbed by a window and subsequently released as heat indoors. SHGC is expressed as a number between 0 and 1– the higher the number, the more solar heat the window transmits.

Structural Insulated Panel (SIP)

Load bearing wall, roof, or floor panel made of foam sandwiched between two sheets of plywood or oriented strand board (OSB).

Unconditioned Space

Area within the outermost shell of a house that is not heated or cooled—the area outside of the thermal envelope. Such areas typically include crawlspaces, attics, and garages.

U-Value

Measurement of the thermal conductivity of a material, or inverse of R-Value. The lower the U-Value, the greater resistance to heat flow (lower U-value = higher R-Value).