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The Transformation of Our Urban Home

by Rob Avis

In August 2008, my wife Michelle and I returned to Calgary, Canada, after spending one year traveling abroad in search of sustainability solutions. With backgrounds in mechanical engineering, our “sabbatical” started off in Denmark – we were drawn there by the lure of technological solutions to energy issues. After several months of volunteering and filling our brains with information (wind energy, solar applications, passive buildings, biogas, plant oil engines… and more) we ended up back in North America prepared to explore the U.S. and Mexico in our plant-oil powered Westfalia.

We knew that something thus far in our sustainability search was missing and were starting to suspect that the missing link might be permaculture (although we didn’t really know what it was quite yet). Our travels brought us to several eco-sites, including an ecovillage near Mexico City. We stopped to do some WWOOFing at a permaculture farm and then headed further south to visit the indigenous Mexicans of the Chiapas, interested to learn about their agricultural practices. An Earthship workshop and geodesic greenhouses in New Mexico and an education center and CSA project in Colorado to name a few other adventures. And to culminate this amazing year we signed up for a Permaculture Design Course at Bullocks Homestead in Washington. The entire experience was nothing short of amazing.

Next task – put all of this information to productive use! Oh boy.

Luckily, my mother-in-law is a good sport and agreed to allow us to use her home as an outlet for ideas and a test case for a permaculture transformation project. Our goal – grow as much food as possible on this urban site and retrofit the home to reduce fossil heating energy by 90%.

Our first task was to asses the property and get productive food systems up and running. We invited friends and family over for a work party, sheet mulched the yards and planted over 100 plants in the front yard mimicking a forest ecology. As we were covering the yard with heaps of composted manure and cardboard the neighbours would slow down as they drove by in awe to see the vast quantity of materials and the number of people running around like ants building a nest. By the end of the day we had a fully sheet mulched back and front yard and a food forest ready to burst next spring.

In the spring we decided that our garden needed to have some swales and trails – shovel in hand we got to work digging. Within a day or so we had shaped our garden beds, filled the trails with mulch from a local arborist and got ready to plant the garden once we were sure that there would be no frost. Calgary has very limited precipitation (300mm) and only about 100 frost free days so we had to be on top of the garden as soon as we were able to make sure we didn’t miss and inch of rain or a day of sun. In late Spring we covered the garden with 20kg of inoculated field pea and shortly thereafter planted the rest of our garden with seedlings started earlier in the year.

With the garden progressing on its own we started on the energy retrofits. Our primary focus was on improving the thermal envelope, heating appliance and thermal mass of the building as we had been inspired by a previous visit to the German Passiv Haus Institute while in Europe. The first project was to blow-in one meter thick of cellulose insulation into the attic. Although the salesman thought I was crazy (new built homes usually have 20-30 cm), I wanted to meet the Passiv Haus Standard with an R-value of R70. Also, cellulose is relatively inexpensive and is an easy “do it yourself” project.

Next we went straight to work on siding of the house. Being that the home was built in the 70’s the wall insulation was approximately 1.5” thick fiberglass insulation (R8) and leakier than a sieve. We first removed the siding, sheathing, old mouldy insulation and vapour barrier to expose the studs and plywood inner wall. Next we blew-in high density foam into the cavities between studs. To prevent thermal bridging from occurring through the studs we added a layer of 2” rigid foam sheathing before replacing the siding. And it only seemed fitting that the new siding color be green! The steps above reduced our air infiltration over 5 times and brought our net R-value from 8 up to 31.

We then installed triple glazed low emissivity & insulated fiberglass frame windows. These windows have a net R-value of R7 which means that they act as a thermal appliance and allow more energy in than energy lost per annum.

Another project we managed to squeeze in was the basement. The basement has also always been very cold in the winter in part due to the lack of insulation in the floor. We attacked this problem by laying a subfloor of rigid insulation.

Based on these upgrades, I calculated that we could replace our 29 kW furnace for a 3 kW one. However, when researching furnace options, the smallest available on the market is a 95% efficient 15 kW. This certainly illustrates how poorly we build our homes!

The retrofit is almost done with a few minor exceptions. This summer we will be installing a solar hot water system to heat all of our domestic water. With the siding off earlier in the year we also took the opportunity to install connections for a future grey water system to feed our new garden.

And so, we have learnt some great lessons from our transformation project and are excited to see how the house performs over the winter. Most exciting of all – our neighbour has requested that we extend our front yard food forest into his yard (he never did like cutting grass). Perhaps we will inspire many others in our neighborhood to do the same. 


  1. Awesome work! Very inspiring to us folks living in northern climates (we live in eastern Ontario). Keep us updated with everything you can observe. Great pictures too! :)

  2. Thanks for all the comments! Øyvind, I will definitely look into “The Ecology of Building Materials” sounds fascinating!

    Keep your eyes open for part 2 of this blog, coming sometime this summer!


  3. Hey Jess, thought you might like to have the R value clarified, in the rest of the world SI units are used, but in Nth America they tend to use both BTU’s and Fahrenheit scale. The R value they work with there is h·ft²·°F/Btu whereas in NZ and Oz we use Joules(per second=Watt) and Celcius plus metric distance, K·m²/W.

    To convert between divide Nth American R-value by approx 6 (5.68 if you need accuracy). So his R70 is an R value over 12 in ANZAC units, still great stuff though, should be able to heat that space with a candle!!

  4. Pete,

    Thanks for clarifying that. We do actually use RSI, which uses the same units as Australia, but because we are connected to the USA we need to report almost everything in metric and imperial. Sometimes we have get units that are half metric and half imperial. Very confusing!

    Thanks for the comments!

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