house
Canada
the high-performance housing magazine
FALL 2014
HEAT PUMPS
What they are, how they work
NARROW PASSIVE HOUSE Compact house lets nature do the work
CHOOSING WINDOWS A brief guide
MAURER HOUSE
AND STUDIO
Case Study in achieving Net Zero energy
ecohouse CANADA | FALL | 2014
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ecohouse CANADA | fall | 2014
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The national source of information on Canadian sustainable high-performance homebuilding in partnership with www.ecohome.net.
fall 2014 6
NEWS AND PRODUCTS
8
NARROW PASSIVE HOUSE
Compact house lets nature do the work
CLARENDON SEMIS
14
Residential semi-detached urban infill 20
MAURER HOUSE AND STUDIO
25
HEAT PUMPS
Case Study in achieving Net Zero energy What are they, how they work
28
CHOOSING THE RIGHT WINDOWS FOR YOUR HOME A brief guide
SEE MORE at:
• www.sabmagazine.com â click on ecoHouse Canada • www.ECOHOME.NET
Cover: Maurer House and Studio. Photo: courtesy Florian Maurer. ecohouse CANADA | FALL | 2014
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Excellence in Window & Door Hardware
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ecohouse CANADA | fall | 2014
A sister publication of:
Message from the publisher Publishing Partners:
Our new web video series:
Canada Green Building Council
High-performance show and tell
VISIT www.sabmagazine.com for our Product Directory Publisher Don Griffith 800-520-6281, ext. 304, dgriffith@sabmagazine.com Editor Jim Taggart, FRAIC 604-874-0195, architext@telus.net Graphic Design Carine De Pauw 819-778-5040, ext. 308, cdepauw@sabmagazine.com Senior Account Manager Patricia Abbas 416-438-7609, pabbas8@gmail.com editorial advisors • Tom Knezic, M.ARCH., LEED AP, OAA Solares Architecture Inc., www.solares.ca • Roy Nandram, LEED AP, RND Construction, www.rndconstruction.ca • Mike Reynolds, LEED AP-Homes, ecohome.net
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Further to the notice on the next page, ecoHouse Canada is teaming up with our web affiliates at ecohome.net and ecohabitation. com to build a high-performance Photo: Roy Grogan Demonstration House and document its construction in a 20-part video series. Designed to achieve LEED Platinum, the Demo House will be an energy miser while also providing a superior indoor air environment – big considerations in a land where we heat our homes for at least half the year. The Demo House takes our advocacy for better home construction to another level. All of the main construction steps will be recorded as concise videos which we will make available on our web sites in English and French. We’ll also be talking about the types of products and technologies that can be used. For example, the house will be a slab-on-grade construction [yes, no basement] with in-floor radiant heating. Passive ideas, in other words free heating and cooling, will be prominent. The point is to provide our readers and viewers with lots of ideas. We have invited companies that we felt would make a good fit with the Demo House to become sponsors by supplying their products. Several have come on board, and they will be noted in the videos and in the print articles that will be published in upcoming articles of ecoHouse Canada. The Demo House is on the small side at 1,600 sq.ft. That’s partly because of its semi-rural site, but it’s also in line with our view that smaller homes with spacious, efficient interior design, high energy and water conservation, and interiors of natural daylighting and replenished fresh air, even in winter, will conserve resources and give us a healthier living environment. This is not to say that we won’t consider building a larger Demo House in the suburbs as the program evolves because such high-performance homes belong everywhere. Watch for more in the Winter 2014/15 issue of ecoHouse Canada. Don Griffith, Publisher
Publication Mail Agreement #40024961 Return undelivered Canadian address mail to: Janam Publications Inc., 81 Leduc St., Gatineau, Qc J8X 3A7
The print version of ecoHouse Canada uses Rolland Environ100 Satin, a 100% post-consumer fiber that is certified FSC and EcoLogo. It is processed chlorine-free, FSC-recycled and is manufactured using biogas energy.
Please forward comments, article ideas and project contributions to: Don Griffith, Publisher dgriffith@sabmagazine.com - 1 800 520 6281 ext.304
Environmental savings for this issue:
FSC logo
14 Trees
52,769 litres water
799 kg waste
2,078 kg CO2 ecohouse CANADA | FALL | 2014
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news
Web video highperformance building guide on the way!
ILLUSTRATION: COURTESY ROSALIE REYNOLDS.
ecoHouse Canada and our web partner at Ecohome.net have recently broken ground on a house building project that will act as a vehicle to launch a free-touse video building guide.
The video series will help take some of the mystery out of high-performance home construction, as well as dispel the myth that the cost of a better build is an investment you won’t get back. In reality, the added money you will pay to the bank on your mortgage for a super-insulated house can be offset by the money you don’t have to spend on heat. So will you actually pay more annually to live in a house like this? Probably not, you just pay it to a different place. Due to the ever increasing cost of energy, some homeowners that have built to extreme levels of thermal performance say they are actually seeing net monthly savings immediately. Such was noted in the Naugler House published in our Passive House Design Issue published in Fall, 2014. A nice way to look at it is as if you are buying your heat from the bank rather than renting it from utility companies. And one day your mortgage will stop, where your utiilty heating bills will just keep coming.
The house: ¢ ¢ ¢ ¢ of
1,600 square foot bungalow with no basement, built a slab-on-grade; two bedroom [+office], two bathroom, open concept living space; polished and heated concrete floor - durable, affordable, healthy, and warm! designed for passive heating and cooling, with an estimated 22-25 kWh per square meter energy consumption, or a fraction of what most new homes would use.
The building envelope: The house will be insulated from under the slab to the ceiling with mineral wool [or stone wool] by our sponsor Roxul, including a four foot wide skirt around the perimeter. Roxul is derived in part from post industrial steel slag, and along with a high R value per inch it is unharmed by moisture, fire resistant, and the density of batts installed tightly in stud bays reduces air convection, further reducing heat loss. Under slab: the slab will be insulated to R-32 with Roxul ComfortBoard CIS [a high-density board insulation] including an R-8 exterior skirt 4 ft. out from the perimeter.
Walls: ¢ 2x6 framed walls with batt insulation in cavities and an additional 8 inches of Roxul Comfortboard IS on the exterior adds up to a true R value of 47; ¢ a peel and stick membrane, by our sponsor Delta [Cosella-Dörken], applied to the exterior of the sheathing as air barrier; ¢ exterior cladding of wood and metal.
Ceiling: ¢ R95 batt insulation covered with a green roof. The trusses and framing lumber are Forest Stewardship Certified [FSC] and supplied by sponsor Kott Lumber. Numerous other sponsors have supplied products and all will come to light as the construction of the house is documented in print in ecoHouse Canada and in web videos on ecohome.net in what will become a worthwhile guide to high-performance home construction.
Just prior to pouring the slab, all of the sub-slab infrastructure is in place, including 8 in. of Roxul CIS ComfortBoard, 10 mil vapour barrier by sponsor W.R. Meadows, and insulated water pipes and tubing for radiant heaT by sponsor Uponor. 6
ecohouse CANADA | fall | 2014
Compact house lets nature do the work
Passive Narrow House
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Existing garage
Located in a jungle of hip roofs, white vinyl, and pink stucco in East Vancouver, the Passive Narrow House makes green home ownership more affordable through careful planning, use of simple forms, and a combination of inexpensive yet durable materials that reduce maintenance costs. The passive strategies for lighting, heating, cooling, and ventilating run on free solar energy, and the house has the ability to provide rental income of varying amounts based on the family’s changing needs.
By Allison Holden-Pope
The 1,700 sq. ft. three bedroom home has a roof-top penthouse and garden, and an additional 900 sq. ft. of flex basement suite with two additional bedrooms. Creating a compact home on a small lot in an urban location is a great way to create density, however, it often results in less than desirable outdoor spaces with overlooking neighbours on all sides. The solution? We put the yard on the roof – 664 sq.ft. of private outdoor living space with solar access and unexpected views. The green roof also reduces storm water run off, and the heat island effect. The house minimizes energy consumption with a highperformance envelope, including thermally-insulated fiberglass windows with argon fill and low-e coatings as well as R46 roofs in addition to the insulating planted roof on top. Concrete block [CMU] walls, three storeys in height and exposed to south-facing windows, are used as affordable thermal massing inside the insulated envelope. The charcoal-coloured blocks act as both heat sinks and sources as needed, by season.
Green roof The compact house on a small lot uses inexpensive, yet durable materials [1]. The front door opens to a wood-slat wall that screens the staircase [2]. The living room and other areas of the main floor are ventilated in the summer through the stack effect of the central staircase [3].
Site plan
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ecohouse CANADA | fall | 2014
Materials were selected based on the life-cycle principle, with a reduced environmental impact, durability, and the potential for reuse or recycling at the end of their useful life. Our siding picks, including factory finished fibre-cement panels and steel siding and roofing, all have recycled content, a long service life, and are recyclable. Locally and sustainably harvested cedar siding was used sparingly, and stained with a locally made low-VOC and non-toxic natural oil wood finish. We used composite decking made of reclaimed wood fibre and recycled plastic bags. Guardrails are aluminum with high recycled content and proven longevity. Fiberglass windows are non-toxic and low-maintenance while being durable and structurally strong, with a low embodied energy and high recycled content.
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In a city like Vancouver, where owning property is a daunting financial prospect for most and building a custom home is attainable only for a lucky few, sustainability can become something that only the wealthy dare to add to their wish list. Narrow Passive House set out to change this approach to single-family housing with its environmental responsiveness and affordability. A passive design and cost-efective material choices, paired with rental income from the convertible two-bedrooom basement suite, made this dream eco-house a financial reality for the young owners. v Allison Holden-Pope is principal at One Seed Architecture + Interiors Inc. in vancouver.
The ceiling of the penthouse at the top of the central stair slopes up to a glazed south-facing wall with an operable glass door [7]. DURABLE STEEL SIDING PAIRED WITH CEDAR SOFFITS AND GUARDRAIL [8]. The vegetated roof provides additional insulation and private green space in a dense neighbourhood [9].
MATERIALS - Wood frame and engineered wood construction with Basalite CMU block with charcoal grey integral colouring oxide additive, minimum 20% recycled content, structural interior wall and thermal mass - Fiberglass windows and doors that are recyclable, energy efficient, argon filled, low-E coated - Roxul Comfortbatt mineral wood batt insulation in roof and walls, min. 40% recycled content, Greenguard low-VOC certified, CFC and HCFC free, and EcoBay CC Can closed-cell spray insulation by Bayer - Claddings are fiber cement siding with EasyTrim aluminum reveals, corrugated pre-finished steel, western red cedar channel siding finished with CBR’s Broda Protektor stain - Fabric-reinforced monolithic rubber roof membrane [1/4” thick] below vegetated roof assembly; Liveroof Standard 4” self-draining modular green roof trays - Furnace operates with heat recovery ventilator - Bamboo and porcelain tile flooring with Schluter Systems DITRA mat and Kerdi membrane for interior tiled areas - “No-added” formaldehyde millwork products used
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Clarendon Semis
BY Gordon Erskine
Owner/developer experiments in sustainability vs market realities A
A residential semi-detached urban infill on a small east/west-oriented lot, with each living unit having three bedrooms plus study and attached garage, is a typical redevelopment in an established Ottawa neighbourhood. With one unit retained by the Developer/Owner/Architect and the other sold at market price, the project was a careful experimental blend of the sustainability preferences of the Owner versus market pricing realities.
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Site plan
A B C D E
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Deck Ground floor Garage Porch Concrete sidewalk
ecohouse CANADA | fall | 2014
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Construction Although the market prefers double garages, this would have resulted in the loss of the existing mature deciduous street trees and forced a three-storey design in an area of two-storey houses. Keeping the mature trees meant going with a single garage. The home was constructed with insulated concrete form walls [ICF] from foundation footings to the roof trusses. Materials were selected to maximize indoor air quality: floor finishes are entirely hardwood and porcelain tile; plywood was used for subfloor and roof sheathing, and cabinets are solid wood; paints are low-VOC water based; and counter tops and window sills are natural stone.
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Construction was completed without a single garbage container on site. Engineered floor and roof trusses were delivered from the factory and generated no on-site waste. Footing forms were reused as scaffolding walkways for the ICF construction and as safety guards. On site paper/cardboard, plastic, metal and organic recycling containers were utilized. Drywall waste was taken to a recycling facility. The biggest challenge was recycling foam from the off-cuts of the ICF system, and the packaging for primarily electrical, plumbing and appliances.
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The front [west] facade. Keeping the mature trees meant going with a single garage [1]. Materials used indoors provide the best possible air quality: hardwood and porcelain tile floors; solid wood cabinets, low-VOC paint and counter tops and window sills of natural stone [2 AND 3].
The design of the semis was motivated by:
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-minimizing heating/cooling costs -reducing life cycle costs through maintenance- free materials -minimizing water and electrical consumption
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-minimizing waste during construction A high-performance building envelope, simple solar orientation and shading, and the use of natural ventilation were the first steps in meeting these goals. On the more active side, we used heat recovery ventilation [HRV], waste hot water heat recovery, Energy Star appliances, high-efficiency mechanical systems, web-enabled thermostat, on-demand [tankless] hot water tank [HWH], low-flow plumbing fixtures, and energy-efficient lighting [CFL/LED]. Preliminary scoring suggested LEED Platinum for Homes would be very achievable. Walkscore: 75
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Section A-A
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Loft/study Kitchen Basement
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Air conditioning is often not needed because of the highperformance building envelope and mass of the ICF structure, the orientation and shading by overhangs and deciduous trees, and because of adequate natural ventilation. The gas furnace is 97.6% efficient with ECM variable speed motor and the air conditioner has a SEER rating of 14.5. The gas fireplace will heat the home in the event of a power failure. Gas consumption in the past 12 months was 965 CY for heating dryer, fireplace, range, BBQ and hot water. This equates to less than $500, including taxes. In the event of a gas interruption, the home could be heated with a standard 1,500 watt hair dryer [but we ended up installing a furnace]. v Gordon Erskine is a partner in Erskine Dredge & Associates Architects Inc., Ottawa.
6 The rear of the house showing the wood panels, steel siding and stone siding [6]. The back yard is an extension of the living space [7].
Lessons learned Hard sell: From a developer’s perspective it is difficult to sell the “behind the scenes” sustainability features. The other side of the Semi sold for the same price as the other new Semi-detached homes in the neighbourhood, even though there was about $50,000 worth of sustainable elements which will bring savings in lower maintenance and energy expenses, and a superior living environment. Market dictates: Heat loss estimates suggested a 1,500 watt hair dryer would be enough for heating but my Realtor said he would have trouble selling a home without a real furnace. We installed the smallest gas-fired furnace on the market, but I feel the cost was unwarranted. Because of the electrical demand of the homes [due in large part to all major appliances being gas fired], my electrician suggested using a 60-amp service but, again, the market demanded a 100-amp service, and even that seems inadequate to many buyers. Also, with the good natural ventilation designed into the homes, and the high insulation and air tightness of the ICF construction, air conditioning is really not needed. But no A/C would have been a ‘no-go’ for selling the house.
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ecohouse CANADA | fall | 2014
Product choices: For better energy efficiency, it would be better practice to insulate all the hot water lines. More switches should have been installed to allow turning off ghost demands, as well as a master to turn off all but necessary electrical demands for extended vacations. After living in the home for a few years I wish I had invested in really high performance windows and made them bigger. A skylight into the central stair would have brought much needed natural light into the core and improved ventilation, particularly on the ground floor. With no operable window in or beside the front door, natural ventilation on the ground floor is limited to windows in the back and sides of the home. LED technology has progressed and prices have dropped dramatically so at least light fixtures can be changed as desired. No spec-build: I would develop another sustainable infill project if I presold, but would not likely build another on spec.
2015 Editorial & marketing opportunities Suggest or contribute your ideas and articles related to sustainable high-performance housing. Use ecoHouse Canada as your access to the market through print and digital advertising, our web blog, sponsorship of the Canadian Green Building Awards, and participation in our Demonstration House. We have a lot to offer!
spring
u u
Contains Special Supplement published with the Canada Green Building Council [CaGBC] - The LEED-for-Homes in Review: An overview of all houses that were LEED certified in 2014 Bonus distribution: Canada Green Building Council national conference.
summer
Special Annual Issue: The Canadian Green Building Awards, a joint program with the Canada Green Building Council, covering the winning residential projects from this annual national program. Bonus distribution: Canada Green Building Council national conference in June. Also distributed at the IIDEX Design Conference and Construct Canada Conference.
Special feature: Demo House round-up, Review of the building methods and products used in our 2014/15 state-of-the-art high-performance Demonstration Home. Bonus distribution: Toronto Green Building Festival, IIDEX Design Conference and Construct Canada Conference.
winter
fall
Aging-in-Place Housing: Affordability, technical excellence, accessibility, and environmentally-preferable products for this housing type. • PLUS Lights, appliances and all things electrical. Bonus distribution: Canada Green Building Chapters.
PLUS!
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HOUSING CASE STUDIES PRODUCT PROFILES INDUSTRY NEWS AND INTERVIEWS ecohouse CANADA | FALL | 2014
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MAURER HOUSE
AND STUDIO Case Study in achieving Net Zero energy Built in 2003, the 1,850 sq. ft. Maurer House overlooks Lake Okanagan in BC on a sloping site with bedrock outcrops that we built around by dividing the house into three pieces around a central garden and mature trees: a studio/garage on the east, the master bedroom pavilion on the south, and the main living pavilion on the west. BY Florian Maurer Garden Bedroom cabin
Garage
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Studio Main house
The house overlooks Lake Okanagan and is built in tHREE separate PAVILIONs: bedroom, living/kitchen/dining and stUdio, to accommodate the contours of the rock outcrops [1].
The gently sloping shed roofs and exterior wood screens blend the pavilions into the landscape. Construction consists of an exposed glulam post and beam frame, large expanses of high-performance glazing, and profiles galvalume cladding. Glazing is applied directly to the glulam framing, and the glazing beads are rectangular Douglas fir pieces that appear as part of the frame. We used high quality, durable materials in a simple structural form: a modest approach that has brought the house a number of architectural awards, among them a Governor General’s Medal for Architecture in 2006. The jury for this Award said, in part, “The project’s convincing economies offer a valuable contribution to promote environmental sustainability, commonsense and restraint. In a context dominated by generic, often overbuilt houses, the building is a visible alternative and incentive for discussion.” Site plan
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Without high-tech gizmos it found its way into the book “150 Best Eco House Ideas” [Collins Design, New York, 2010], among numerous other publications.
Improvements since 2003
The Photovoltaic System
Our goal was to reach Net Zero energy but our building budget of $120/sq.ft. in 2003 wasn’t enough to pay for some components that would have made the building even less wasteful. We rectified this three years ago with the idea to generate all the building’s energy needs on site. These are the project’s components:
This was the first step on the road to “net zero”. The time to act had come when the local utility started to allow net metering.
- a grid-tie photovoltaic system expected to meet all heating, lighting and cooling loads; - a geothermal heating system replacing the existing boiler, using the existing radiant in-floor heating system; - a gas fired on-demand boiler replacing the existing boiler-mate for domestic hot water, and to act as emergency back-up to the heat pump; - replacing the gas-fired hot water tank in the small stand-alone studio with a baby electric boiler, tied into the existing radiant infloor heating system; - improving the building envelope by eliminating the open combustion air inlet, which the new on-demand unit no longer needs.
In net metering, power is sold to the utility in times of surplus, and bought back in times of shortfall. It avoids the inefficient and toxic batteries associated with off-grid systems. To feed power into the grid it has to be converted from low voltage direct current [DC] into line voltage alternating current [AC]. This was traditionally done by a single inverter between PV modules and the grid. New “microinverters” convert the current at each module into 240V AC. The advantages are safety and efficiency: safety in avoiding the hazards of low voltage/high amperage current, and efficiency by the 98% conversion rate of the inverters through avoidance of high line loss associated with low voltage, and because the performance of each array is no longer limited by its “weakest link”, such as a shaded module. That’s the system we chose. We looked at Environment Canada data and hoped that 30 panels of 230W nominal capacity for each would do the trick. This system started operating on August 18, 2013 and we monitored the performance on the microinverter manufacturer’s website [Enphase].
ecohouse CANADA | FALL | 2014
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House inside a house could save energy
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Practical improvements to achieve LeeD Platinum ebOM
Miriam Turner on Net-Works™
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Don Griffith, Publisher 800-520-6281 ext. 304 dgriffith@sabmagazine.com
ecohouse | summer 2013
1
Heat pumps what they are
and how they work
When it comes to residential heating and cooling systems, few types of systems are as energy efficient as heat pumps. But what exactly are they and how do they work? In short, a heat pump is simply an electrical device that is capable of transferring heat from one place to another. Though it may seem counterintuitive at first, heat can actually be extracted from cold air and added to warmer air. By Jason Ng Cheng Hin
To explain this in a more practical manner, let us step back a little bit to understand the basics. First of all, for the sake of an analogy, let’s imagine heat as a big body of water. Logically, water would flow from a higher place to a lower place. Similarly, heat naturally flows from a hotter place to a colder place. So how is it that we can extract heat from a cold place and send it to a warmer place? Well, it is a little bit like moving water from a low place to a high place. All you need is a pump! Heat is actually defined by the movement of the molecules that make up matter. So in essence, all of the air in the world that is warmer than absolute zero [-273 °C, the temperature at which molecules actually stop moving] contains some amount of heat. So technically, it is possible to extract heat from air of any temperature and send it somewhere else, all it takes is a little energy. Heat pumps are actually quite commonly used in our everyday lives. In fact, this process is happening almost all the time in your home right now, as refrigerators are actually a typical form of heat pump. Heat pumps are able to extract heat from air by using a liquid refrigerant [more on this later] to absorb and remove heat and what’s known as the vapour-compression refrigeration cycle, which is a fancy name for a thermodynamic process that is commonly used for heat transfer applications. There are four basic steps: 1. The process starts where the refrigerant is in a state known as a saturated vapour. This saturated vapour enters a compressor where the pressure is increased and, consequently, the temperature as well. 2. Hot vapour is then passed through a condenser, where it is condensed back into liquid form. The result of this condensation is that the refrigerant will lose its heat. This is what is what is occurring right now in your household refrigerator, and why it is warm in the back.
3. The liquid refrigerant then passes through an expansion valve, where the pressure drops and the liquid becomes much colder. At this point, the fluid is typically colder than the space that needs to be cooled. 4. Lastly, the cold fluid, which is now partially evaporated due to the pressure drop, passes through an evaporator, which typically consists of a coil or long tubes. A fan then blows air over the coil or tubes, cooling the air. This causes the refrigerant to evaporate within the tubes, returning it to its original saturated vapour state. Basically, what is going on is that a refrigerant is being forced to go through cycles of condensing and evaporating where the temperature and pressure rise and drop significantly. These temperature fluctuations are then used to heat or cool a stream of air or water, depending on the application. So that explains a bit about the science behind heat pumps, but what exactly is it that makes heat pumps so interesting for residential heating and cooling applications? The advantages of heat pumps are quite numerous. First of all, the amount of energy typically required to run the compressor and the fans or pumps is usually significantly less than the amount of heat that can be moved, or in practical terms, ‘generated’. Heat pump performance is usually measured by something called the ‘coefficient of performance’ or COP.
typically in Canada, the best practice is to install heat pumps above grade to protect the outdoor coil from damages due to drainage freezing and snow melt in winter. photos: courtesy of Mitsubishi Electric.
ecohouse CANADA | FALL | 2014
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Windows are essential to our houses. They give us natural light, a way to ventilate the home without depending on mechanical systems, a means of emergency exit, and offer an alternative way to heat the house free of charge through passive heating. by Denis Boyer
a brief guide:
Choosing the right windows for your home
even houses certified to the passive house standard can use large windows if their quality is high and the orientation takes advantage of the sun’s energy. the bernhardt house by cascadia architects and bernhardt contracting ltd. windows by euroline windows and doors ltd. photo: derek ford. 28
ecohouse CANADA | fall | 2014
But they are also holes in our wall structure, making them by far the weakest part of the thermal envelope of a home. So how should we select our windows to reduce energy bills all year round? Choosing the wrong windows will work against efforts of adding more insulation to the walls and roof to improve energy efficiency. To illustrate this point, let’s imagine that a home has about 1,800 sq. ft. of walls which are insulated to R50. If the house was fitted with just one 3 feet by 3 feet window with an R-value of 1, the R-value of all of the walls combined would drop to R40 even though the poor-performing window occupies only 0.5% of the total wall area. If the house actually had two such windows, the R-value would drop further to R33; and if there were one on each façade, the overall effective insulation level would be a mere R25, half of the desired value but with only 2% of the whole wall area covered with windows. The same principle applies to all other parts of the thermal envelope. For instance, there is no need to insulate the roof to R100 when the walls are just R30. If, however, the windows performed better, the overall R-value of the wall system could be much improved. The table below gives an idea of what could be achieved with different window surfaces and R-values for that same wall insulation level of R50. Having more window area, on the other hand, guarantees more solar gain [except for North-oriented windows] and natural light and, thus, can lead to even lower energy bills.
WINDOW AREA
WINDOW R-VALUE
OVERALL R-VALUE
[% of wall occupied by windows]
[ft2 x°F x hr/Btu]
[ft2 x°F x hr/Btu]
1
1
2
1
25.2
4
1
16.9
10
1
1
4
2
4
40.6
4
4
34.2
10
4
1
33.5
8.5 2
44.8
23.2 3
1
8
2
8
45.2
4
8
41.3
10
8
32.8
47.5
Table 1: The effects of window area and quality on the overall R-value of a R-50 wall [with no windows]. 1
Entry-level window; e.g. aluminum frame with no thermal break. High SHGC. See Table 2 for SHGC definition.
2
High-quality double pane or mid-level triple-pane glazing. SHGC > 0.6.
3 Very high-quality triple-pane glazing and frame, entry level Passivhaus certified. 0.3 ≤ SHGC ≤ 0.6. Table 1 shows that increasing window performance a little can have a dramatic impact on the overall performance of the thermal envelope. For instance, with a high performing window having an R-value of 8 the wall would perform the same with 10% of window area as it would with 4% for windows having an R-value of 4, or just 1% for windows with an R-value of 1.
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Choosing for orientation
Some recommendations
Care must be taken, however, in choosing the right glazing characteristics for each orientation.
• Choose the best windows you can afford. Work with the window supplier to get the right glazing for each orientation.
On the North side, go with the the highest R-value, period. On the East and West façades, a combination of a high R-value and low solar gain coefficient [SHGC1] is best to prevent overheating, unless the windows are well protected from direct sunlight in the summer and in between the hot and cold seasons, for instance, with shutters, sunscreens or vegetation. On the South side of the house, some R-value can be traded for higher solar gains in order to benefit from the low winter sun; therefore, look for a high SHGC with the highest possible R-value [or its opposite: the lowest possible U value, since this is the value usually provided for windows and doors]. South glazing should, however, be well protected from summer sun, which is a simple exercise in geometry in designing roof overhangs and the like. As a general rule, our cold winters warrant triple-pane windows with high quality window frames. The frame alone can represent up to 25% of total window area so the same logic applies here: a low frame R-value will result in poor overall window performance whatever the quality of the glazing. Typical SHGC values to look for based on orientation are shown in the table below:
WINDOW ORIENTATION
SHGC
NORTH
-
SOUTH
> 0.6
EAST/WEST
< 0.4
Table 2 : Orientation-dependent typical SHGC values.
Frame: Up to 25% of window area U -value should be low Thermal break: Thermal conductivity [W/m . K] Glazing: COG U -value normally given [W/m2 . K]
Glazing: EOG Ψ - value rarely given [W/m . K]
the main components of a window and the technical data to look for in order to calculate the overall window performance. Window makers sometimes only provide the COG [Center of Glass] U-value, which is not representative of the actual performance [the frame is where the window loses most heat].
Window components. COG = Center of Glass. EOG = Edge of Glass. U-value = 1/R-value. The COG and frame U-values along with the EOG Ψ -value can be used [if available] by the most enthusiastic modeller to compute a precise whole-window U-value. Image source: Wikimedia Commons, Oimabe. Modified by Denis Boyer, Ecohabitation. 30
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• Choose at least Energy Star certified windows or better [e.g. Passivhaus: www.passivehouse.ca] and try to have all the technical data available [Ucog, Uframe, Ψeog] which should enable the correct calculation of the overall Uw [U-value of the whole window]. Serious manufacturers will gladly provide these, which must be the result of independent testing or simulation. • Remember that the product should be very airtight. Otherwise the energy saved in heat transfer will be lost in air leakage. Be careful to select glazing with a high coefficient of visible transmittance [VT] and ensure that glazing on all orientations have a matching colour or tint. A high VT means more daylight is available which can save energy for artificial light and its associated cooling load. • Install the windows to minimize thermal bridging which causes heat to be conducted through the wall framing via the window frame. This can best be achieved by centering the window in the middle of the insulation. Eliminating thermal bridges lowers the risk of condensation, which in turn insures longer life for the product and smaller energy bills. • Consider also that if you maintain indoor climate at 20°C and 40% relative humidity, condensation will form on any surface whose temperature is 6°C or less. If you keep the room temperature at 21°C and 50% RH, condensation temperature will rise to 10°C. When comes the time to choose windows for any project, keep in mind that better windows may pay for themselves in a few years, while improving occupant comfort and the overall user experience. Shop around and get all the facts. Once again, consider Passivhaus-certified products; they may be worth the extra expenditure, especially if you live in a cold climate. If in doubt, consider hiring a professional to help you select what is right for your specific project. When it comes to energy efficiency, windows can actually be an asset rather than a liability. v Denis Boyer, P. Eng. M. Eng. Is Energy Efficiency Co-ordinator at Ecohabitation in Montreal, www.ecohabitation.com.
Advertorial
Potential of the Polish construction and interior furnishing industry
T
he construction and interior furnishing industry made a significant contribution to an increase in the Polish economic growth indicators in 2013. Global turbulences of recent years have caused the Polish construction and interior furnishing market to also be one to record lower turnover. However, since 2008 it has continuously held the leading position in comparison to Central and Eastern European markets, where drops in turnover ranged from 20% (Czech Republic, Slovakia, Hungary) up to 50% (Slovenia). The level of optimism on this market has been growing since 2013 and forecasts for 2015 even suggest an improvement in the economic situation on the construction and interior furnishing market. Poland is coming out of the crisis – representatives of the construction and interior furnishing sector are enjoying general trust, which creates a healthy atmosphere and conditions for growth. According to the latest ranking by Deloitte: “Polish construction companies in 2013 – key players, prospects for growth and diversification” as many as 11 out of 15 of the biggest construction companies recorded profit from sales. In comparison to the year before, 9 out of the 15 largest construction firms (in terms of collected revenue) noted on the Warsaw Stock Exchange soared by as much as 58 percent. Data published in Q1 of 2014 by the Polish Cement Manufacturers Association shows that cement sales in March 2014 grew by 99.5% in comparison to March 2013 and amounted to 1,343,500 tons of cement. Until 2020 Poland will still be one of the biggest beneficiaries of EU funding. Moreover, a government program under the name “Polish Investments” has also been created and it supports long-term investments with funds from the Bank Gospodarstwa Krajowego (National Economy Bank) and the Polish Development Investments company. The largest investments value-wise are planned in the road construction sector, railway sector, energy sector and environment protection sector. The forecasted economical growth and the necessity to build new, and preserve the existing, infrastructure for transport, energy and environmental protection will certainly revive the sector. According to the report of September 2012 developed for the Polish Ministry of Economy regarding the construction market in Poland, manufacturers of construction materials when asked about what distinguishes Polish products from their competitors from abroad, said that it was mostly their high quality. Over half of the respondents claimed that a definitive advantage of Polish products also lies in competitive prices.
know how important it is to implement innovations. A great example of a Polish company that recognizes the important role of new technological solutions for development is Quartec. This company promotes pole construction, based on c-c composite boards, which are innovative, ecologically friendly and completely safe for human health. Those are very important aspects from the clients’ point of view, as Poles increasingly rely on ecology and a healthy lifestyle. Besides construction firms, it is also worth emphasizing the development of domestic companies from the building finishing and interior furnishing industry. Quite recently Poland has become a tycoon on the window market. The company OKNOPLAST is a leading innovator in Europe, with 1800 stores across the continent. DRUTEX exports vertical windows to such places as: the USA, Mexico, Australia, and the Middle East. The “FORTE” S.A. factories are the top Polish manufacturers and exporters of furniture; the company has 4 production facilities and a number of commercial companies in Poland. It invests in knowhow and state-of-the-art technologies – it equips machine parks with the most modern devices and manufacturing technologies, and implements and develops a special IT system that supports enterprise management. Poland is a country that has still got a lot of potential for the construction and interior furnishing industry. There are certainly still many niches to be discovered here (also with regards to technology), as well as a chance for foreign investors to shine. The manufacturers’ experience, the improving situation on world markets, ever better situation of Polish households, and finally, enormous support from the European Union and government programs give Poland phenomenal conditions to grow its construction and interior furnishing industry. Under the Polish Economy Promotion Program in Canada, Polish businesses are supported by the Polish Ministry of Economy. Through work under the common name “Polish Economy Brands”, financed by the European Union from the funds of the Innovative Economy Operational Programme, Polish companies can present their achievements at international fairs, such as Construct Canada 2014 in Toronto. The main goal of this program is the creation of Polish brands that will be recognized all over the world while at the same time associated with their place of origin. We warmly invite you to visit the Polish National Exhibition Hall at the Construct Canada 2014 fair.
Representatives of the Polish construction industry
Project co-financed by the European Regional Development Fund under the Innovative Economy Operational Programme.
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Faster, Thinner Floor Warming
Schluter®-DITRA-HEAT Electric floor warming system with integrated uncoupling Floor warming systems have become very popular. Heating tiled floors increases the need for uncoupling to prevent cracked tiles and grout. Use DITRA-HEAT to get both – warm floors and uncoupling – in a single layer. • Heating and uncoupling in a single layer • No self-levelers required to encapsulate heating cables (no need to wait for curing) • Place the heating cables exactly where they are needed, without clips or fasteners • Combines the flexibility of loose cable with the ease of installation of a mat system • 120 V and 240 V options • Programmable and non-programmable thermostats available
www.ditra-heat.com | 800-667-8746 32
ecohouse CANADA | fall | 2014
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