Overview As the group gathered to design a home in the Midwest for environmental and social-equity minded client, we recognized that Detroit was in the midst of an unbelievable transformation of which this home could be a major part. The team took pains to find ways that the home could be part of the needed urban infill and to alleviate blight along its borders to help stabilize its entire neighborhood. As such, a large, vacant site was selected at 538 Harding on the city’s East side for the construction of a 2,140 sq. ft. 3.5 bedroom home1 for occupancy of five people. Designing for extreme energy independence and efficiency was a goal that far exceeded cost-consciousness. Instead the home was to be designed to be smaller to save costs. The owners plan to live in the home for decades, and wanted to be able to “age in place.” The following proposal captures the design team’s efforts to limit the environmental impact of the building and earn LEED Gold status. Regional Appropriate Design & Green Features In addition to meeting minimum standards for building a LEED certified green home by conducting an initial rating of the proposed facility aimed at meeting the Gold standard, which achieved 81 points, the owners have engaged an integrated project team composed of a LEED AP architect, a building science and performance tester and also engaged a landscape architect due to the sensitive nature of the property and the need to minimize runoff into the Detroit River and sensitive Lake St. Clair ecosystems. That team began the design process with a charette, where the first requirement the team set forth was orienting the building to have large exposures facing south, complete with four foot overhangs on the southerly side of the home to shade those fenestrations in summer and not shade those same windows in winter. The building skylights have draw-able shades to mitigate unwanted heat gain in summer.
1
The home has four bedrooms, but one serves as a home office for the owner.
For durability, the owner has made clear with the project team that durability of the enclosure is high-priority, and risks shall be accounted for, and response measures planned. All of that shall be documented, and the builder will confirm in writing that they have met all measures from the Durability Inspection Checklist. Finally the building will be rated by a Green Rater, who will confirm compliance with these measures. In an effort to be innovative and regionally appropriate, the owner has made plans to purchase the adjoining vacant lots, some of which are believed to be in the city tax auction system, and has committed to building an urban tree farm, similar to the Hantz Farms project in Detroiti. Through this effort, the owner hopes to cut down on urban blight, which is a very major issue in Detroit, as well as cut down on heat island effects, and over the 30-50 year life of the trees help offset some of our carbon release. When the trees have matured and been harvested, the land can revert to residential use as urban density increases in the now sparsely populated Detroit. This credit will be applied for after construction, as it requires application to the USGBC for approval. This use of the land, as well as incorporation of only native species in the maintained portions of the yard allow the home to use no more than the 32 inches of rain that naturally fall per year in the areaii with supplementation during times of drought from a rain-water collection system that captures 214 gallonsiii at a time of a possible 19,948 gallons of water per year from the garage and main house roof. This equates to a catchment area of approximately 1000 sq. ft. 538 Harding is a lot in Detroit that was previously built-upon, has existing street and sewer infrastructure, but the existing structure has been demolished to remove blight. The property is located only a half block from the Detroit River. It sits across the street from an inlet from the lake which will be used for an open loop geothermal HVAC. Because the Detroit River is connected to large bodies of water, namely Lake St. Clair and Lake Erie, it has a minimal flood risk, thus allowing this site to be above the 100 year floodplain despite its proximity to a river. The site,
which will have piped access to the inlet from the Detroit River, still sits 100 ft. away from the body of water, which is a requirement for LEED certification. The home is conveniently located two blocks from Jefferson Avenue, a main thoroughfare in Detroit and home to multiple downtown destined buses. The areas walk score is 46 out of 100, which is reasonably high for Detroit, and is in the path of development for more restaurants, retail and grocery options as the area surrounding it, The Villages, continues to re-develop. At this point, the building qualifies as meeting the needs for many basic community resources through its half mile proximity to transit and other amenities, as well as proximity to Owen Park for human and animal recreation.
walkscore.com
The use of renewable energy was a key priority of the building owners. The house will feature an open-loop geothermal system that draws on the ample groundwater in the soils next to the Detroit River, and discharge that water back to the inlet adjacent from the home. It will be moving 4 to 8 gallons per minute, which is an admissible amount for discharge considered under the legal maximum threshold for open-loop systems in Michigan. Specifically, the house will use a Geothermal Systems Hydron Outdoor Split HRT 048 modeliv, which will supply between 29-36K btu/hr of heating and 39-51K btu/hr of cooling capacity (partial-full load differential)v, which exceeds the estimated need of 30K btu/hr of heating and cooling for the home, but leaves room for the system to be effectively during times of abnormal cold or heat. This is cognizant of the
requirement for 6503 heating degree days and 651 cooling degree daysvi. The system is efficient in that it requires on drilling one vertical well hole, and then simply piping the outflow to the river. This offers significant savings during construction and minimal site disruption. Based on average electric costs of $0.104/kWh2, and comparing this system to a 16 SEER air-conditioning system, a high efficiency electric heating system and a high efficiency electric water heater, this system will cost $1738 to operate per year compared to $2915 per year for the other high efficiency systemsvii. The system also benefits from a 30% tax incentive for being Energy Star accredited. The system will meet the homes entire heating and cooling needs, while humidity and heat will also be retained through a Honeywell TrueFRESHEnergy Recovery Ventilator, which meets ASHRAE 62.2 standardsviii. Finally, high efficiency CFL lighting will be used throughout the house3. The home will also feature a modest 5 kW solar array on the south-facing garage roof from Novi installer Srinergyix. With an average of 4 solar hours per day in Detroitx, plus a discount factor of 20% for snow cover or other losses and outages, the system can be expected to produce 480 kWh per monthxi. Average homes in the surrounding area use approximately 603 kWh per monthxii, but this home is expected to be 20-30% more efficient than other homes due to its orientation for passive solar and focus on premium materials for energy efficiency. The home designers feel the building can achieve near net-zero energy use with this system with Michigan’s net metering lawsxiii. In designing the home, extra care was place on ensuring indoor environmental quality. To enhance ventilation, a whole-house ventilation balancing system from Broan (AE 60) which can support the 160-180 CFM required for a house of this size, and ensure efficient comfort and safety indoor environment. Ceiling fans and whole house fans will also move air, and operable windows
2
Separate sources peg Michigan electric costs at over $0.14/ kWh2, which would drive the savings of the new system even higher 3 LEDs are preferable for efficiency, but CFLs are more available and have better light quality
enhance ventilation of natural air. Several skylights situated over the kitchen and dining room will bring in natural light from the terrace and green house above, as seen in Figure 2. The home also features smart monitoring for comfort and safety. NestEggs Wireless sensors are in all of the rooms so that temperature and humidity can be controlled individually and meet different needs. These sensors also have motion sensors, to detect whether the room is occupied and adjust the heating & ventilating situation accordingly. CO2 monitors are installed and connected to the HVAC system, to bring in fresh air if CO2 levels get too high. Finally, the home uses gravel to prevent the potential harm caused by Radon. A 4-inch layer of clean, coarse gravel sits below the foundation. This layer of gravel allows the soil gases, which includes Radon that occurs naturally in the soil to move freely underneath the housexiv. Though radon levels are above the national average at 2.5 pCi/L, they are still well below the level that the EPA suggests corrective actionxv, and thus do not require more serious corrective measures. This measure also allows the home to keep all wood 12 inches above the ground, effectively mitigating many pest threats. Further, because the green house on 2nd floor and garden will potentially cause the problem of ant and other insects to be near the home, the owners have committed to using Natural Pesticides and Poison-free ant & roach killers. These include food-grade Mint Oil to kill bugs in seconds without deteriorate indoor air quality. To prevent the “new building smell�, which of course are chemicals and volatile organic compounds from many interior finishes, the home will instead use zero VOC paints, low VOC and low solvent adhesives & sealants, and low VOC coatings and carpet. The home also takes great care to limit, specifically targeting a 52%4 reduction via low-flow faucets, shower heads and minimal water use toilets, as well as rainwater recapture for outdoor use. In a standard American home, 28% of water usage is for flushing toiletsxvi. This home will feature 4
28% from using waterless toilet, 14% from leakage prevention, 10% from advanced water-saving product and rainwater harvesting.
only toilets that use 1.3 gallons per flush, specifically the Ariel Aphrodite toiletxvii. The team also chose a water-efficient Energy Star clothes washer, which is a CEE Tier 3 product that uses 37% less water than standard washerxviii. All the faucets are ADA Compliant Water-Sense Certified product with a maximum flow rate at 1.5 gallons per minute, as well as low flow rate shower heads at 1.5 gallon per minute. The dishwasher is an Energy Efficiency tier 1 product that saves 54.5% of water per use compared with a traditional dishwasher. Further, though not typically a problem in new homes, 538 Harding will feature a water leak detection system in our house. Sensors in the kitchen and laundry room will trigger an alarm and automatically shut-off the water supply for the home immediately to prevent further leakage. In the longer term, this will cut down on water loss given that 14% of the home water use is due to the leakage in many areasxix. In order to be regionally appropriate, the plants in the garden and yard are local and droughtresistant species, so that the water from rainwater harvesting system as well as natural rainfall will meet their need for irrigation. The greenhouse will be home to many non-native species— predominantly fruits, vegetables and herbs—but they will be safely sequestered to avoid becoming invasive or crowding out local species. Specifically, the grounds around the home will feature Michigan drought tolerant plants such as false blue indigo (Baptisia austalis), white fir (Abies concolor), and silver sage (Salvia argentea), etcxx. In order to minimize primary resource through-put, the home seeks to use many recycled materials for construction, specifically from Architectural Salvage Warehouse of Detroit (ASWD)xxi, a local supplier. The company has materials from 2600 demolished house units in Detroit and 4000 demolished houses in Southeast Michigan which the designers believe will apply furnish the brick and reclaimed wood for exterior cladding. In addition to the constructional materials, the design team expects to get finishing items such as antique bathroom vanities, kitchen
sink, recycled glass tiles, garden benches and many more. In this way, the home not only reduces its cost and ecological footprint, but also has the social benefit of supporting a local historic preservation organization. Recycled steel for a few girds underneath the second floor patio will be bought from Advanced Recyclingxxii. Other local recycle/reclaim material retailers that the owner intends to source from include: Habitat Restore (Detroit) for reclaimed material, Recycle Ann Arbor and Ann Arbor Reuse Center for recycled material, and Green Safe (Detroit) for eco-friendly housing products. The vast majority of lumber will be recycled material from the retailers mentioned above. The rest of lumber we will use Forestry Stewardship Council (FSC) certified products. Because the outside cladding has not been chosen for its energy efficiency, the design team has focused heavily on making insulation decisions that meet the energy efficiency goals of the structure. To that end, the building will feature vacuum insulated panels (VIP) which have a r-value five times that of conventional insulation even significantly outperform structural insolated panels (SIP). The team chose Panasonic U-Vacua vacuum insulation panels, which work like a thermos by removing air molecules that can transfer temperature through convection or conduction. Radiation still cuts down on performance with VIPs, but the team has chosen a long-lasting, highly radiation reflective metal roof to compliment the VIPs and further increase energy efficiency. This lightweight and environmental friendly products has great durability, and is made with 75% recycle glassxxiii. To determine window selections, the team used National Fenestration Rating Council (NFRC) labeled low- E windows, which are also Energy Star products. NFRC certified windows have low U-factor and better performance on isolation (heat flow through the glass will reduce by half)xxiv. Finally, by using reflective cooling roof material, which reflects heat from sun, there will
be less heat transferred into home. This translates to an expected 20% reduction in required cooling load that contributes to energy efficiency as wellxxv. Lastly, the team determined that waste prevention is more beneficial than recycling. To avoid creating waste when cutting standard materials to unusual size, the home was designed with standard sizes for many of the materials and uses a standard rectangle shape to minimize complexity and thus waste. Extensive use of recycled and reclaimed materials also contributes to less construction waste. Economic Costs and Benefits The project is very ambitious, and is set to cost 24% more than conventional construction that was priced with moderate quality finishes, as captured in Appendix Figure 1. However, there is significant opportunity to recoup a significant amount of this initial up-front cost in 10-15 years due to life-cycle savings from operational efficiency and materials durability. The geothermal system is expect to cost nearly four times the materials price of conventional systems but is estimated to save just under $1,200 annual, showing a cash-on-cash payback period of less than 10 years, and being net accretive in the remaining 10-20 years of system utility. The reflective metal roof, simply on lifecycle durability, will repay itself in 15 years based on its repayment schedule versus a shingle roof. The solar array similar will save an estimated $75 per month on the electric billxxvi, providing a payback period of some 16 years. At the same time, these systems and other improvements that meet Energy Star requirements are subject to a 30% tax deduction through federal programs, as well as the Michigan Home Heating Credit. Though not included in the budget for the project, the tax deductions could amount to savings of up to $21,000. Subtracted from the total costs in Figure 1, the cost differential versus conventional construction falls to 18% for this home. Though it is impossible to estimate precisely at this time, these investments in efficiency, especially the geothermal unit, the vacuum insulated panels (VIPs) and the solar array should lead
to a near net-zero home, which the owner believes far outweighs the costs. This person is truly interested in investing to save on carbon emissions. In making investments, the team did not choose to invest greatly in moisture protection, contaminant control, garage pollutant protection or awareness and education. This was because the humidity and other pollutant issues in Michigan are relatively modest, and those that are significant have been addressed. The education and awareness was not necessary given the owners involvement in the process. Finally, landscaping also did not see great investment beyond the tree farm. Instead naturalscaping will be used beyond the gardened areas and limited turf plot. Obstacles and Uncertainties The project will face several challenges, with the most notable coming from getting approvals for the open loop geothermal system. This system is legal is Michigan because it produces less than 120,000 btu/hr of either heating or cooling, but does require approval from the Department of Environmental Quality. The second challenge will come from finding an appropriate installer for VIPs because they are so new on the market. Though designed to be durable, they must be handled and installed with care in order to ensure they are not punctured, which will ruin the efficiency via the vacuum quality. Lastly, assembling the right team of engineers, architects and builders for this project will be challenge, but one we consider manageable. Conclusion If followed, this plan will deliver a LEED Gold home that will protect its environment and be a part of the revival of Detroit. Its owners will be able to stabilize their neighborhood through the implementation of their tree farm, create needed urban infill and hold the land until the wave of repopulation and increased density meets their corner of the city. They will be able to accomplish this while living in a zero-net energy home with access to urban transportation that is improving continually, and ultimately have an excellent quality of life in a comfortable home.
Appendix Appendix Figure 1 - Budget Item Name
Material
Excavation $ Foundation, Piers, Flatwork $ Rough Hardware $ Masonry Frame $ Insulation $ Exterior Finish $ Exterior Trim $ Doors $ Windows $ Finish Hardware $ Garage Door $ Roofing, Flashing, Fascia $ Finish Carpentry $ Interior Wall Finish $ Painting $ Wiring $ Lighting Fixtures $ Flooring $ Carpeting $ Bath Accessories $ Shower & Tub Enclosure $ Countertops $ Cabinets $ Built In Appliances $ Plumbing Rough-in and Connection$ Plumbing Fixtures $ Heating and Cooling Systems $ On-site Electricity Generation $ Irrigation $ Subtotal Direct Job Costs $ Final Cleanup Insurance Permits & Utilities Certification Inspections Plans & Specs Subtotal Indirect Job Costs Contractor Markup Total Cost Initial Cost Estimation Source
$ $ $ $ $ $
Labor
Equipment
Total
8,463 826 28,221 5,125 14,570 987 2,501 4,308 417 1,181 11,443 1,519 7,290 4,355 4,422 3,315 3,257 6,481 1,606 1,025 3,100 10,192 4,959 4,654 9,454 5,531 149,202
$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $
3,934 13,331 1,304 38,936 3,509 8,713 1,556 2,102 2,933 351 482 9,612 7,661 11,274 10,184 8,361 1,044 4,629 2,315 990 861 2,602 3,210 693 11,318 2,999 8,297 163,201
$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $
1,041 2,117 208 2,229 1,095 248 7,623
$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $
4,975 23,911 2,338 69,386 8,634 24,378 2,791 4,603 7,241 768 1,663 21,055 9,180 18,564 14,539 12,783 4,359 7,886 8,796 2,596 1,886 5,702 13,402 5,652 16,657 12,453 13,828 320,026
9,726 5,905 1,389 17,020
$ $ $ $ $ $
1,389 1,389
$ $ $ $ $ $
-
$ $ $ $ $ $
1,389 9,726 5,905 1,389 18,409
$ 43,418 $ $ $ 43,418 $ 209,640 $ 164,590 $ 7,623 $ 381,853 http://www.building-cost.net/CompMatrix.asp
Upgrade Name VIPs Recycled Brick Energy Star* Energy Star* Reflective metal roof Zero VOC High Efficiency CFLs FSC Wood Low VOC FSC Wood Energy Star Low Flow Geothermal Solar Array - 5 kWh 214 Gallon Cistern
LEED and certifiers -
Material $ Difference 0% 0% 0% 0% 430% 0% 0% 5% 10% 0% 0% 150% 0% 0% 100% 0% 2% 15% 0% 0% 0% 0% 15% 10% 0% 0% 200%
$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ 23% $ 0% $ 0% $ 0% $ $ 0% $ $
Upgrade Cost 4,975 23,911 2,338 69,386 30,672 24,378 2,791 4,728 7,672 768 1,663 38,220 9,180 18,564 18,894 12,783 4,425 8,375 8,796 2,596 1,886 5,702 14,931 6,148 16,657 12,453 24,890 14,800 1,165 393,745
Payback Sources Period
n/a n/a
http://www.greenbuildingadvis *Depends on supply *Aggregate of multiple *Aggregate of multiple
15 http://www.metalforming-usa.c
n/a
http://www.poplarnetwork.com
n/a
0.5 http://realestate.msn.com/ener http://homerenovations.about.c
n/a
1,389 9,726 5,905 7,500 n/a 1,389 25,909
http://homerenovations.about.c 11 http://cbey.yale.edu/uploads/E
http://www.toolbase.org/Techn 9.40 http://www.energyhomes.org/r 16.5 http://detroit.cbslocal.com/2013 http://shop.sportsmansguide.co
http://greencomplianceplus.ma
$ 53,838 24% $ 473,492 n/a = not available/not applicable