Building an Off-Grid Home in Canada
A couple rents and works in the city, but opts to build a high-performance home in the country
This is the first in a series of posts by Craig Anderson describing the off-the-grid house he built with his wife France-Pascale Ménard near Low, Québec. Craig writes about the "Seven Hills Project" in a blog called Sunshine Saved.
My family and I live part-time in Ottawa, Ontario, where both my wife and I have our work, for the federal government and local university respectively. Though I've always wanted to live in a rural and relatively wild setting, it would be impractical for the commutes to work and the kids' schools, as well as the isolation being too much for my wife to handle all of the time.
So a compromise was born: to rent a reasonable place in the city, and make our real home out in the countryside. It would be our full-time home for the summer, and a weekend retreat during the winter.
Building a highly efficient green home is something that I thought about for many years before it actually happened.
I never formally studied architecture or building science, but I dabbled in researching the topic for a decade. I was absolutely inspired when I first came across some of the designs for highly efficient homes from the ’70s, especially some of the passive solar designs of that time. There were terms like Trombe walls, usage of large water tanks for thermal massHeavy, high-heat-capacity material that can absorb and store a significant amount of heat; used in passive solar heating to keep the house warm at night. , Earthships with greenhouses inside the home, and more.
There was a great deal of experimentation going on in building innovative and green homes for the future, with the hope of drastically reducing the amount of energy that it takes to both build and run a home. This experimentation really was necessary, because as I read further, I came across critiques of all of the things that didn't work, causing things such as mold and massive overheating in the summer.
While there were a lot of interesting ideas here, clearly I was going to need further inspiration elsewhere. And I did go on to find further work on passive solar design done much more recently, that has distilled out some of the best design principles to take advantage of that free energy source, the sun.
Energy use far from the grid
More recently, I came across Passive HouseA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates., another green building design philosophy that focused almost exclusively on reducing the amount of energy used in a building (Passivhaus in its original German). By focusing on energy reduction, the building envelopeExterior components of a house that provide protection from colder (and warmer) outdoor temperatures and precipitation; includes the house foundation, framed exterior walls, roof or ceiling, and insulation, and air sealing materials. becomes the prime target. Massive amounts of insulation, compact shapes with a minimum of surface area, triple-pane windows, high airtightness — these are the things that allow heating (and air conditioning) loads to go way down, so low (as I read in multiple places) that a house that can be heated by only a hair dryer.
As for electrical loads, there are now efficient appliances and mechanical systems that, in conjunction with a well-built shell, bring energy consumption for space heating in a certified Passive House down to roughly 10% of that in a typical older home.
The third major strand that we needed to bring together for our project was renewable energy, so that we could build a home that was off-grid. Unfortunately (or perhaps fortunately depending on your perspective), the property that we fell in love with was very far off the beaten track, so far off that it would have been prohibitively expensive to bring in power lines.
It was going to be both cheaper and much more interesting for me to build a home that was completely off the grid. Today is a very exciting time for renewable energy, with solar panels dropping precipitously in price, new types of batteries just becoming available that are more powerful and reliable, as well as less expensive than those that came before. I am not alone in thinking that renewable energy is the future, and it is quite a ride to see that future arriving and to be a part of it.
Finally, there was the architectural style to consider. It is possible to build an efficient home in any style that allows for a relatively compact building shape, and I was drawn in particular to some of the contemporary styles. I have seen a certain style of home described in some places as "contemporary mountain" that have stylistic elements that we drew from, including a single-pitched shed roof, deep overhangs, use of lots of larger dimension wood, and a close alignment to natural surroundings.
My impression is that this style is currently most popular in the Pacific Northwest. I'd say that the single home that provided the greatest inspiration for style came from Nils Finne of Finne Architects, and a home that he built on the shore of Lake Superior.
Building site and orientation
Forest surrounds the home on all sides, with amazing views of a small valley to the south, and a back bay of the river visible about 150 feet to the west of the house. We chose a hilltop location, in large part because of the views it afforded. The other advantages of this location are excellent southern exposure for both passive and active solar, as well as it being much less buggy than the surrounding lowland areas because it was drier and windier.
That wind is a double-edged sword, however, as we are much more exposed to the whipping winds of storms and winter, which probably increase our heating loads a bit and has also put me in place to watch trees topple over and land within 20 feet of the house during a particularly vicious summer storm.
The hilltop building site an hour north of Ottawa is surrounded by forest and offers excellent southern exposure as well as good views.
The clearing that we opened was just large enough to build the house and yard, a bit less than half of an acre. On the north, west, and south sides of the house, this means that the forest begins only 20 feet from the house. To the southeast is a grassy yard big enough to cover the septic field, and to the east is a parking area with our solar panels tucked onto the north side of the clearing to reduce the shading from the trees.
Unlike most of the homes built along the waterfront in our area, ours does not have clear line of sight to the water. We currently have a screened view of the water, which actually makes those glimpses out onto the bay more special.
Trees were kept strategically so the house would be well-shaded during the summer season, from the south and most especially against the hot afternoon sun out of the west. The best way to accomplish this is with deciduous trees, red oak and sugar maple in our case, so that all through the leafy summer season the house stays as deeply in shade as possible, while in the winter the lack of leaves allows the sunlight to stream right in. The existing larger trees at our site helped to determine where we would set the home so as to best take advantage of that shading.
Planning for the best solar exposure
The rule of thumb that I have read and been told multiple places is the house should face within 15 degrees of south to take advantage of passive solar heating, but with our site we were able to square our house perfectly to the sun. This means that at solar noon the sun shines straight into the south windows of the house.
This perfect east-west orientation gives a few unexpected benefits. One is that our entire house acts as a sundial; one can simply look at the angle of the shadows cast on the ground as the sun streams in the windows to know the time. Also, on the spring and fall equinox, we get the sunrise and sunset shining all the way across the home through the windows on the east and west sides. I noted this spring that in the downstairs bathroom (at the northeast end of the house), sunsets around the equinox are really the only time that the room gets direct sunlight at all.
Passive solar design principles suggest that a longer east-west axis is used, with windows focused as much as possible to the south side. This allows for the south wall and windows to soak up the winter sun, while minimizing the east and west faces which can heat up excessively in the summer. We doubled down on this logic by making our home a rectangle elongated east to west, with a much taller south face full of windows.
A solar chart of the site is packed with information.
At the same time, the north side was banked into a hillside with only a few small windows; north windows are always in the shade, so they constantly lose heat through the winter. We broke only one rule of passive solar design by putting in a lot of west-facing windows, but this was a worthwhile trade-off to capture the views of the river, and trees provide good summer shade to the west.
With all of the big windows, especially in the upstairs, it certainly has the effect of bringing the outside into our home. The views change with the seasons, with veiled views during the summer and fall due to all the leaves on the trees, with much clearer lines of sight in the winter. This allows us to really soak in the valley and hill to the south, and the river to the west.
Thinning trees to best advantage
In figuring out details about the house, its orientation, and which trees to keep or cut, I spent a lot of time looking at the solar chart (above). It packs an enormous amount of information into one graph, showing the length of the day, angle of the sun above the horizon and simultaneously its location in the daily east to west motion — and does all of this for every day of the year. With a bit of measurement and calculation, I could imagine how the sun would play across the house throughout the day and across the seasons, and plan for windows, shading, and solar panels.
All in all, we have been very pleased with the siting of our home. I have recently read that there is some doubt as to whether applying passive solar principles is worthwhile in the age of superinsulated homes, but I still wouldn't change a thing. Even though we did a lot to maximize our solar gains, we at the same time were able to meet all of our aesthetic goals, both inside and out.
- Craig Anderson
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