Posts Tagged ‘passive house’

A Tour of the First “Passive House Certified” Residence in Canada

March 8th, 2011

First Certified Passive House Residence in Canada

We went to Ottawa for Family Day weekend to visit my husband’s family. A few weeks before this, I received a press notice that an Ottawa house had become the first Passive House certified in Canada. “Say,” I thought, “wouldn’t it be great if I could arrange for a tour of the house while I was in Ottawa?” So I did.

If you’re not familiar with the Passive House movement, houses are designed and built so that they only use 15 kwh/m2 of energy for heating and cooling and 120 kwh of electricity per month for lighting, appliances and other household uses. To give you an idea of what this means, the typical new home built in Ontario today uses about 10 times the amount of energy consumed by a Passive House certified building. If you’d like to know more about the Passive House movement in Canada, you can read about it here.

Chris Stratka of Vert Design was intent on building a super-insulated home when he bought the property in the New Edinburgh neighbourhood of Ottawa. However, when he took the design to a Passive House consultant he was told it probably wouldn’t qualify because the building materials and systems available in Canada that he had specified were seen by the consultant as inferior to those available in Europe. Although Chris was disappointed, he decided that he’d build the “best” house possible and leave it at that. Specifically, Chris is aiming for a Platinum LEED for Homes rating, with a particular emphasis on the Energy and Atmosphere section of the certification.

Chris decided that the best way to achieve his home’s performance targets was to use a modular home builder, and located one just outside Ottawa who would build to his insulation specifications. As I’ve written about before, modular home building has several environmental advantages such as the materials being protected from the elements (moisture, heat, cold, etc.), less waste in production, and less disruption to the local neighbourhood because the final product is put up so much faster. Chris’ home was assembled on site in three weeks. Yes, there was still the need for electricians, HVAC installers etc., but the major construction vehicles were on the street for a short period of time and there was never a dumpster on site.

Once the walls were assembled, insulation was added to the ceiling, caulking and sealing was done, Chris called in green building specialist, Ross Elliott from Homesol Building Solutions, a building performance consulting company that provides third-party inspection, testing and verification services. Ross performed the blower door test to identify any leaks that might have escaped the caulking and sealing. Chris said that if you’re going for energy efficiency in a new or renovated home, it’s essential to bring in the energy auditor a few times while the house is under construction. It’s much easier to fix leaks and holes in a partially built home than once the drywall is up and everything is already in place, and it will save you money in the long-run through lower energy bills. It was after the initial test that Chris and Ross believed that they just might be able to qualify for Passive House certification after all.

There are two other aspects about the house that were of primary importance to Chris:

1. He built it using only North American supplied materials in order to demonstrate that we North Americans have the resources and the technology to build super-insulated homes. All the major building materials,  hot water heaters, geothermal heating/cooling, and windows are manufactured in Canada and the US.

2. Testing for air leaks at several stages of building was essential to achieving the home’s air tightness.

In order to build a Passive House certified residence, there are several elements in addition to air-tightness that are essential to take into consideration:

 

Inline Fiberglass Windows

Orientation: Part of the Passive House formula is the ability to take advantage of the free heat a house can receive in the winter by orienting windows to absorb the light. In this case the house if perfectly situated, facing due south, and backs onto conservation land next to the river. It means he’ll never have to worry about another building going up that would eventually block his sunlight and heat source. The canopy in place protects the room from the heat in the summer when the sun is high in the sky.  The shading system that is currently being installed protects the rooms from the heat of the low winter sun.  In this building the issue is not getting enough heat – it is getting too much!

"Tilt" feature of "Tilt and Turn" windows

Windows: All windows are “tilt and turn” windows provided byInline Fiberglass, a window manufacturer based in Toronto, ON. They are triple-glazed, Low emissivity, argon gas filled, and the fiberglass frames themselves are insulated. The day I visited it was -15, but when I put my hand to the window pane, the glass was warm. When I do the same thing on my own home’s windows, the glass is always chilly; in fact, it’s just plain cold anywhere around any window in our house.

A nifty feature of the windows is the “tilt and turn” aspect. They tilt open at the top to let air flow in or out, or can be opened completely as a door on side hinges. This is a great feature to quickly cool down a room in the summer time, if the hot air has risen to the third floor.

Heating and Cooling System: In hindsight, Chris says, the geothermal heating and cooling system he had installed wasn’t necessary. However, when first designing the place, and being told that it would never pass Passive House certification, he figured he’d use the least intrusive HVAC system he knew of — geothermal. His particular system is made by Maritime Georthermal from New Brunswick. In future passive house designs, he would use baseboard heating in each room as Passive House homes are designed so that traditional heating methods such as central furnaces, aren’t necessary. He’s also added a Heat Recovery Ventilator (HRV), from Airia Brands from London, ON. When I asked him why he hadn’t chosen an Energy Recovery Ventilator (ERV), he replied that ERVs are more suited to humid climates where moisture is present year round.

For a complete breakdown of the specifications of the wall composition and HVAC, hotwater and windows used, please see Chris’ PDF document on his website.

Other “eco features.” Passive House certification’s focus is on energy use for heating, cooling and plug load. It does not look at other factors such as indoor air quality, water use, or minimizing the use of building materials. Chris referred to LEED criteria for these areas. Some of the more eco-friendly features of his house are:

  • Green Roof garden. Essentially his house takes up the entire plot of land, with only a small patch of property out back. Since he would like to grow some of his own food, he has designed the roof so that it can hold a substantial garden with herbs, tomatoes, beans and other vine plants, and maybe some crooked carrots (the depth of the soil will be about a foot). The green roof will also add further insulation to the home.
  • Rainwater recycling. There is a space built into the second floor that is awaiting rain barrels which will capture run-off from the eavestroughs and will be stored inside the home to feed toilets with water. The point of putting the rain barrels on the second floor is that the water is fed to the toilets through the use of gravity. That way they are unaffected if the electricity goes off.
  • Energy Star Appliances. All appliances, including washer/dryer, are Energy Star rated. The cooktop by Kenmore, uses induction heating, which is also quicker than gas.
  • No gas line to the house. Chris says that there are two reasons he relies on electricity for heating and cooling, cooking and hotwater: the first is that gas doesn’t fully combust and is not indoor air quality friendly, and secondly, to become dependent on gas means that you can never convert your home to 100% renewable electricity. Chris has plans for solar panels on the roof.

For more information on this project, visit VertDesign.ca

For more information on Passive House certification, visit the Passive House Institute US.

In Canada see: Passive Buildings, and Canadian Passive House Institute.

Passive House Design in a Canadian Climate

June 23rd, 2010

I mentioned in an earlier post that Terrell Wong was retrofitting her husband’s family home to have a building envelope that’s almost as tight as a Passive House’s home. While I was visiting the Rosedale House, I became intrigued by the whole idea of Passive House design and its possibilities in a Canadian climate. Terrell took time out of her (extremely) busy schedule to talk to me about Passive House design and its relevance in our Canadian climate.

Passive House designation was developed in Germany twenty years ago. While it is just gaining attention here in North America, it has been the standard of choice in Germany since its inception. There are a few reasons for this: one is that electricity, and energy in general, is far more expensive in Europe than it is here so it’s in the homeowner’s best interest to build the tightest building envelope technology can offer. Another reason is that in Germany’s milder climate, it is more technically feasible to build a house that uses only 15 kwh/m2 of energy for heating and cooling. Thirdly, and perhaps most importantly, building codes are much tougher in Germany and require higher levels of insulation and energy conservation than we have here in Canada (hint, hint Canadian building code writers).

The reason that 15 kwh/m2 per year was chosen as the passive house standard is that a boiler or furnace is no longer required to heat a home at that level. In fact, home orientation with south-facing windows, an energy recovery ventilator and occupant body heat can be enough to keep a home warm except for on the coldest of days.

Building orientation and heating requirements: Here in Canada, particularly in an urban setting where property choice and development is restricted, building a passively heated home is a challenge. As a contractor I know says “Anything’s possible, it’s just a matter of how much money you’re willing to spend.” In Terrell’s case, she was restricted by the fact that her home is east facing, something that was completely out of her control. Passive homes are designed, when possible, to take advantage of the sun’s rays in the winter with south-facing windows that allow for heat absorption during the day. In the summer, the planting of deciduous trees and awnings can help block the sun.

Insulation requirements: Sometimes getting the insulation levels to where they need to be for passive heating doesn’t make financial or spatial sense.  Naturally, colder requirements require much more insulation and sometimes, giving up the space due to thicker walls can be an issue. For example, depending on the climate in which you live, if your home requires R60 in the walls to meet the standard, your wall may need 10 inches of R6 insulation which can take up to 2 feet of space away from your living area by the time you’ve added exterior and interior walls (not to mention the cost!).

But working towards building a tighter, well-insulated envelope has the advantages of providing significantly lower heating bills. As energy prices rise, a well-insulated home can also insulate the homeowner from sky-rocketing energy prices.

Thermal Bridging: In addition to building orientation (to take full advantage of the sun),  building envelope tightness and insulation, passive house design also addresses thermal bridging. Thermal bridging occurs when heat finds a path to escape out of its enclosure. Thermal bridging occurs around  and through windows and doors, as well as floor and wall studs which are attached to the outside part of the building envelope.  Eliminating these thermal bridges is a key element in passive home design. Homes are designed with as few if any electrical wiring running up the outside walls.

Windows: In Germany there are Passive House certified windows. Because Passive House design has existed in Germany for so long, the window manufacturers’ technology has evolved to match the requirements. While there are distributors of these windows in Canada, getting a contractor who understands how to properly install them is essential for a sealed fit.

I came across an article on windows for passive house design by Martin Holladay, from Green Building Advisor. There are five Canadian companies that manufacture high quality thermal windows that, while not Passive House certified, offer superior insulation properties as well as fiberglass frames.  Fiberglass is considered to be one of the best materials for window frames as it expands and contracts at the same rate as glass helping to reduce thermal bridging. For an excellent explanation on windows  for Passive House design, see Martin Holladay’s blog post in Green Building Advisor: Passivehaus Windows: Cold Climate Builders Look for the Best Available Windows.

Modeling: If you’re at all interested in pursuing Passive House design, the first thing you need to do is input your home’s design (including orientation) through the Passive House Planning Package. This is an energy-simulated model run in Excel that will provide you with your heating load/m2 based on the figures you input. It will also calculate your overall costs assuming you know your costs/m2, so you can make informed decisions about whether it’s more economical to increase your insulation or invest in better windows. Note: this is NOT a do-it-yourself kit. It takes considerable  specialized training and engineering knowledge to use this software properly and understand the results.  It’s best to work with a certified Passive House designer, consultant or architect or engineer who is familiar with passive house design and modeling  if you’re interested in building a passive house.

Building, or even retrofitting a home to passive house standards may not be realistic for most of us, but if we can strive to increase the insulation in our homes, recognize and avoid thermal bridging and invest in the highest quality windows our budget can afford, the upfront costs might be higher but the pay-off will continue for years to come.

For more information on Passive House design see:

Canadian Passive House Institute

Passive House Institute US

Passive House Institute Germany

Thanks again Terrell for your time and expert knowledge!

A Rosedale House Super Renovation — Targeting 90% Reduction in Energy Costs

May 28th, 2010

Rosedale House

The renovation that’s going on at Terrell Wong’s Rosedale heritage home isn’t the kind you usually see in Toronto: the square footage hasn’t been doubled, there’s no added stucco involved, and many of the original fixtures and cabinetry are being reused. But then, Terrell isn’t your normal homeowner — as an architect, her firm, Stone’s Throw Design Inc.,  designs “green” homes and along with Ann Stevens and Clelia Lori won the design competition for the Archtype House now fully built and operating at The Kortright Centre. So Terrell knows a thing or two about building energy efficient homes.

When the opportunity arose to renovate her in-laws’ home, Terrell set her goal at insulating her house to as close to Passive House standard as she could get. The goal of passive house design is to construct a building envelope that’s so tight a homeowner only needs 15/kwh/m2 of energy to heat the home. To put that number in perspective, right now Ontario building code minimum standard is 150 kwh/m2 (yes, that’s 10 times passive house standard). The Rosedale House won’t achieve such a low energy use, but it will achieve a 50/kwh/m2 energy use. FYI: passive house standard is difficult to achieve in our climate. It was developed 20 years ago in Germany which has a moderate climate than ours. For more information on Passive House see: http://www.passivehouse.us/passiveHouse/PHIUSHome.html

So, how is Terrell going to achieve this low energy use goal?

Building Envelope: The interior walls of the house were completely torn back to the brick. The walls are being insulated with 5.5 inches of Heatlok Soya insulation (R6 per inch) for an R value of 33. The attic will have 2 inches of the spray foam in addition to cellulose insulation for a projected R60. In the basement they dug down three feet to add some living space without going out back, and placed 4″ R10 rigid board insulation in the floor, then covering it with radiant infloor heating tubes and a final layer of concrete (which will also act as the final floor finish.

Heatlok Soy Insulation, sprayed 5.5" thick

Terrell’s blog is a goldmine of green building information. She’s described the reasons behind why she decided to do certain things and who she used to do it. Getting the right trades involved in a project like this is essential to its success. Terrell talks about why she needed to use spray foam insulation versus batt insulation such as Ultratouch or mineral wool, which would have been a lot cheaper, but also you’d lose a lot of space. It all comes down to air leaks and let’s face it, old homes are full of them. Like many old Toronto homes there was minimal insulation in the attic, no insulation in the brick walls and none in the basement. In fact heating used to cost $7000 per year, using two big oil tanks which were filled 4 times per year. Using a minimum of 5.5 inches of spray foam achieves several goals:

  1. It can get into cracks and crevasses that batts can’t and really seal them up.
  2. It can be used as a vapour and air barrier at two inches or more thick.
  3. You do not need to rely on the coordination of many different trades to identify and seal leaks. The foam accomplishes it all in one go. This is particularly important in the renovation of an older home.

Thermal bridging: thermal bridging refers to the areas where heat can travel and escape from enclosed spaces to the exterior. In most older homes thermal bridging occurs where internal wooden beams touch the outside masonry. This is particularly true for floor joists. The Rosedale House’s new construction has the internal 2x4s spaced 2 inches away from the external wall so that 2 inches of insulation can go between the studs and the wall, thereby minimizing heat escape.

Energy Recovery Ventilator Air Intake

Energy Recovery Ventilator (ERV). When an energy audit was performed before the house was gutted, thanks to the absence of insulation, 8 air changes per hour were measured — that’s a really leaky house. When the renovation is completed, air changes per hour will be reduced to 0.6. When you have a building envelope that’s that tight, you need to make sure you have fresh air coming into the home at all times. But in the winter, opening windows defeats all the hard work that’s gone into insulating the home, so a practical device is an Energy or  Heat Recovery Ventilator (HRV/ERV).  Fresh air from outside is pulled into the ERV and warmed by outgoing old stale room temperature air. The model of ERV that Terrell chose is by Ulimate Air, the RecouperAerator 200DX which is 96% efficient at heat exchange from air and moisture.

12kW ministar electric boiler

A tighter envelope means that a smaller system is needed. A new 12 kw electric Allied boiler Ministar will provide all the heat for the house, and a two tank hot water system that was imported from Germany will provide hot water. The two tank system provides one tank with “preheated” water from future solar hotwater heater on the roof, and a tank for conventional water heating.

Dual Hot water tank

As with the whole process of renovating this house, Terrell has reused as much as possible. The kitchen cabinets are going back in (although with a fresh coat of stain!), and all the radiators are being reused. Further, the small rebuilt addition at the back of the house will be sided with the tongue and groove wood that’s on the ceiling of the covered porch that needs to come down. But the huge, west-facing window will be imported from Germany, made to passive house standards. (Manufacturer: Internorm Varion windows http://www.greenbuilding-windows.com/products/greenbuilding-windows.html)

It will be fantastic to watch the progress of this house. Terrell’s blog gives an excellent explanation of why she’s chosen particular materials and mechanisms, as well as (and most importantly) what trades she’s worked with to achieve her energy efficient dream house.

I will be following her progress as she goes. Thanks for sharing Terrell!

You can reach Terrell at: Stone’s Throw Design Inc: 416-463-9735

Follow progress of The Rosedale House on Facebook:

http://www.facebook.com/#!/pages/Toronto-ON/Rosedale-House/342864660822?ref=ts&ajaxpipe=1&__a=10

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