The Transformation of our Urban Home

In August 2008, my wife Michelle and I returned to Calgary, Canada, after spending one year travelling 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 thusfar 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 WOOFing 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 workparty, sheet mulched the yards and planted over 100 plants in the front yard mimicing 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 or rain or a day of sun. In late Spring we covered the garden with 20kg of inoculated field pea shortly and 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 occuring 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 subfloof or 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 perfoms 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.

How to Build an Earthship - Our Adventure in New Mexico

Throughout the last year Michelle and I have been searching for green building methods that use little to know grid energy for space conditioning and electrification. So far we have seen a straw bale house, and underground concrete building, adobe brick and Michelle has extensively studied the envelope of the passive haus standard in Germany. All of them provided various pros and cons and everyone it seems has an opinion on the subject which we have discovered can vary from the logical to the insane. While we were in Teotiucan I was surfing the net and came across the Earthship website where I discovered a week-end seminar on Earthship construction. An Earthship is the brainchild of the eccentric architect Michael Reynolds. It is basically a house made of rammed earth and tires, usually in a U shape with the backside of the U earthshelter (i.e. burried into a hill). The dates for the week-end seminar lined up perfectly with our trip through New Mexico and Michelle and I decided that it was an experience worth attending.

We arrived late Friday night at the earthship headquarters which of course is an earthship. We watched Garbage Warrior, a documentary based around the earthship creator Micheal Reynolds and his struggles with the building codes in New Mexico. It is a great movie and paints a perfect picture of Michael, who is quite the character. The rest of the week-end was a mix of lectures by Michael about the history of the Earthship concept, how the structure goes up, how the thermal mass works to keep the earthship warm in the winter and cool in the summer, how the energy and grey water systems work, etc. We also spent a good part of the week-end pounding tires! Man is that a good workout.

The earthship inventor, Michael Reynolds decided after graduating from Architect school that the world did not need any more architechs designing standard building envelopes that were energy hogs, and as suseptable to grid failure as the utilities. Seeing all of the large landfills, peak oil, massive and global warming on the horizon he set out to start building green buildings out of what ever he could find. His first buildings were as crazy looking as the materials that he used. Michael started with bricks made from six beer cans. This made sense as there was no recycling back then and he loves to drink beer. He then tried to build with beer cans without making bricks but using the individual cans as bricks. Both of the concepts worked well structurally but did not provide the thermal mass that he was looking for. A short while after he started these crazy building projects the architechts association withdrew his license indefinitely. With nothing left to loose and a little more than a couple of pennies to rub together he decided one day that he would build a house out of tires. As weird as it seems you can’t argue with his logic. As Micheal says, they are indigenous to the planet, they are virtually indestructible, waterproof, have a big footprint and basically make the best brick in the world. Typically the homes are designed as a large U or a series of U’s parallel to each other with the open part of the U facing south in the northern hemisphere, and north in the southern hemisphere. The orientation of the U’s is based on maximizing the solar gain that the house receives. Once the shape of the house is determined the U’s are draw on the ground, and a survey of the land takes place so that it can be flattened out. Next the first row of tires is placed forming the U’s which means that it is time to start filling the tires with dirt and compacting the dirt with fledge hammers. This is by far the hardest part of building one of these structures as it is intense and slow physical work. We were told that if we wanted to determine the amount of time it would take to build the walls to assume that one man could pound 20 tires a day which is a drop in a bucket considering the average earthship has 1000-1500 tires. The tires are stacked in an offset pattern similar to traditional bricks, the difference being these bricks weigh 150 kg! As the tire wall goes up earth is burmed around the outside with an insulation skirt about three 1 meter away providing frost protection and support to the tires from the outside. After the walls are built trusses are spanned and a greenhouse is added to the front of the building. The roof is insulated to R 70 and sloped in order to capture rain water for the inhabitants. For those of you who have a good understanding of building you may have noticed that there was never a foundation, grade beam or piles driven to support the building. This is one of the many advantages of this building. Because the tires are very wide they have enough surface area to span the load and do not require a footing. The walls in the building are finished with a cob mixture which covers the tires and beautifies the building. Michaels goal for an earthship has always been to make them completely self contained with a very small environmental footprint. For this to happen he had to come up with ways to deal with grey water, sewage, electricity, and thermal energy.

The thermal energy completely provided for by the sun via the southern greenhouse. The thermal mass in the tire walls store the heat from the day and release it at night. The highly insulated roof ensures that minimal heat is lost to the environment.

Greywater is any water is considered waste water that contains no sewage. In the earthship water that is captured from the roof is stored in on site cisterns where it is drawn, filtered and used for sinks, showers and dishwashers, this water (grey water) is sent to a biological water treatment cell located in greenhouse where plants clean the water. Excess water in the grey water biofilter is then collected in a sump and sent to the toilet. After the water is used in the toilet it is considered black water and treated in a different system.

Black water is any water that contains sewage. This water is sent to a septic tank where the solids and liquids settle out and then it gets pumped into a similar biological cell to the grey water cell which is planted with perennial fruit trees. This cell is lined with thick poly to protect the ground water and is equipped with an overflow tank which can be pumped if there is any additional sewage left over. The overflow tank is placed there to satisfy the building codes and to date no system has flowed into it. Michael also mentioned that water has been tested after going through the sewage cell and it is always clean.

Because the earthship was designed in the desert where less than 300mm of rain and snow fall annually it is important to ensure that the water is used as many times as possible. With the aforementioned systems water is used

1. For drinking, washing, cooking ect.

2. To feed a food bed in the front greenhouse

3. To provide flushing water to the toilet

4. To feed a perennial black water bed providing fruit trees.

Electricity is provided for with solar PV, wind generators or micro hydro depending on what is available on site. The system is a standard power system but interestingly enough it is one of the first components to be installed in a house as it provides the power for the saws, drills and cement mixers. This allows them to build anywhere there is renewable energy!

The Most Energy Efficient Buildings in the World!

[Rob recently connected with Katrin Klingenberg, the Director of Ecological Construction Laboratory in Illinois and one of the founding members of Passive House Institute US. She had some great feedback for our blog and additional comments about passive houses in cold climates, which I've added in square brakets and in Italics.]

The Passivhaus Institute (or Passive House Institute), located in Germany, has been pioneering the most energy efficient buildings in the world since the early nineties. Buildings certified to the Passivhaus standard are ultra-low energy buildings requiring very little energy for space heating.

For European passive construction, a building must meet the following requirements:

• Total primary energy use for all appliances, domestic hot water and space heating and cooling less than 120 kWh/m2.
• Total energy demand for space heating less than 15 kWh/m2 per year

A few comments to help qualify the figures above:

• An average home in Canada consumes 0.93 GJ/m2 or 258 kWh/m2 per yr
• Space heating in Canadian homes utilizes the most energy in the residential sector and accounted for 60% of the total residential energy consumed in 2005, or approximately 163 kWh/m2 per household per yr

There are over 6,000 certified Passivhaus' in Germany, Austria and Switzerland. These houses use on average 85% less energy than comparable North American structures and far surpass even LEED Standards. And contrary to what you may think, these homes are as solid and durable as ordinary houses, brilliantly full of light and air, and comfortable. In fact, the Passivhaus mandate is that these buildings should be well known as the most comfortable homes in any region within all climates.

You may be asking: "Is it really reasonable to be comparing European standards to Canadian buildings considering the greater heating demand in our cold climate?". My answer is YES, but also NO.

YES because there is no reason that we cannot incorporate sound and demonstrated methods and building techniques into our buildings to substantially increase energy efficiency, decrease losses and take full advantage of solar gains (i.e. free energy).

NO because it would be unwise to copy direct details from the Central European examples to other parts of the World. The Passivhaus concept must be first adapted for the climate under consideration.

Before discussing whether this could be done, I need to first describe how the impressively low energy demand is achieved.

The key elements of a Passivhaus include:

• Superinsulation: very high insulation to reduce heat transfer through walls, roof and floor is achieved using technologies such as Vaccum Insulated Panels and construction methods to minimize thermal bridges. The resulting U-value is between 0.1 - 0.15 W/m2/ºC.
• Passive Solar: planned and well thought out utilisation of solar and internal gains using compact shapes and windows oriented towards the south to maximize solar gain.
• Excellent air tightness: Air barriers and careful sealing minimizes the amount of warm air that can pass through the structure.

• Superwindows: Thermally efficient windows and frames with a U-value less than 0.8 W/m2/ºC. This very low window U-value is achieved by an intricately designed frame that minimizes thermal bridging. The triple glazing utilizes low-e coatings and inert gas filled air spaces to reduce radiative and convective losses. Because of the very low U-value and the high transmittance the windows can actually be considered thermal appliances as they provide more thermal gain than loss through the course of the year! It?s hard to believe, but true.
• Heating Load: All of these elements combined in the Passivhaus result in the energy efficiency being radically increased and the heat demand dramatically reduced. In fact, the peak heating demand in a Passivhaus is less than 10 W/m2.

[Comments from K.Klingenberg: 10 Watt/m2 and year: not true that this is the case independent of climate. it works out almost perfectly in Germany and Austria. Here in Illinois for example we meet the 15 kWh/sm and year, but the heat load is up to 16. That means that we need additional heat sources in the house, which is not a big deal. The initial requirement of 10 was recently turned into a recommendation by Wolfgang Feist and the PHI. We have learned that in very severe climates it is almost impossible to meet the 10, but it is still possible to make the annual 15 which is really the more important criteria since it is defines the overall consumption.]

With this low a heating demand, the ventilation system can easily be used for space heating and a separate heating system (i.e. boiler, natural gas furnace, forced air heating, electric baseboards, etc) is not required- regardless of the climatic conditions. Essentially, an advanced heat recovery ventilation system is used to recover and disperse heat while maintaining air quality.

Alright, to qualify some of the values that I?ve been throwing out, lets compare again to Canadian houses:

• Insulation: An R22 building (house with 2x6 wall construction) has a wall insulation U-value of 0.26 W/m2/ºC. Older homes in Canada built with 2x4 wall construction have an R value of 12, assuming fiberglass batt insulation. This is equivalent to a U-value of 0.47 W/m2/ºC (As compared to 0.1 ? 0.15 W/m2/ºC for a Passivhaus).
• Solar Gains: Few new homes in Canada are built taking into consideration passive solar gains and the ?free? energy available from the sun.
• Air Tightness: Construction standards for air tightness allow for 20 times more air leakage than allowed in a certified Passivhaus.
• Windows: A double pane window found in many typical Canadian homes has a U-value of approximately 2.5 W/m2/ºC. The best triple glaze, inert gas filled with low-emisivity coating that we could find in North American had a U-value of 1.77 W/ m2/ºC (as compared to 0.8W/m2/ºC).
• Heating Load: The resulting typical values for heating load range from 40-120 W/m2 (as compared to 10 W/m2).

The energy differences are staggering. The first big questions is: "What about the cost?". In Germany, where most passive houses have been built, it has been published that with careful design and the increasing competition in the supply of specifically designed Passivhaus products (windows, wall materials, etc), it is now possible to construct buildings for the same cost as those built to normal German building standards. This is largely due to the cost savings from not having to incorporate a conventional heating system. However, we've also found reports of Passive Houses requiring an additional 40% investment. What is most important to consider of course, is not necessarily investment, but economics and energy autonomy. Considering that the peak heating load has been reduced to 10 W/m2 compared to an average assumed heating load of 75 W/m2 you can see that the energy savings on a monthly basis would be substantial.

[Comments from K.Klingenberg: The price per sqft (conditioned actual living and floor area), construction budget only, is currrently $120. If you take the footprint incl. the thick passive house walls, as the appraisers do here, it is $100. That is not bad at all. Locally, $110-$125 is the price per sqft for an ICF house advertised as being very energy efficient, but still uses 50% (compared to PH 10%) of heating energy. Our local construction prices are relatively low as you might have noticed.]

The second big question is: Is it possible, in Canada, to incorporate passive house technologies and construction methods and actually achieve a heating load comparable to passive houses in Europe considering that Germany, Austria and Switzerland generally have a milder climate than we do? Well, although there is not one certified Passivhaus in Canada to date- we think that this trend is coming. Now considered a mature technology in Central Europe, Passivhaus' are being built in Poland, a passive apartment building in Sweden completed in 2006, and more than 15 passive house projects are currently in the planning phase in Norway. The Norway projects range from mild coastal to cold inland climates between 58º and 70º degrees latitude. Lastly, the first certified Passivhaus building in North America, the Waldsee Biohaus, located in Minnesota, was completed spring 2007. In terms of climate design criteria, Minnesota has a heating design temperature of -26ºC, latitude of 47.5ºC and annual degree-days of 5056. Calgary has a heating design temperature of -26.2ºC, latitude of 51º and annual degree-days of 5135.

[Comments from K. Klingeberb: I built the first passive house in 2003 (in Urbana, Illinois). Dr. Feist (Founder and Director of the Passivhaus Institute in Darmstadt, Germany) calculated it himself when I was at the PHI. I did not feel the need to get it certified because of that. The certification is also pricy and back then building the first prototype that was not in the budget. I started to promote, implement passive houses through our non-profit e-co lab, which is currently finishing up the third passive house here in Urbana and we will break ground next month on the 4th one. This makes e-co lab currently the leading passive house builder in the US. As e-co lab we have consulted on a Passive House project in Berkeley California, which is now nearing completion. Another project we are consulting on is a Martha's Vineyard project that is going for certification with the PHI (2nd certified PH in the States). It broke ground in September.]

We also found on the internet, a fairly new company based out of Kelowna, British Columbia, Global Passive House. They indicated on their website plans to utilize intergrated Passive House standard building systems in a newly proposed Ecovillage on the outskirts of Kelowna. Also, Passive House Institute US has recently been formed in order to bring these standards, technology and innovations to the North American market.

One other thing worth mention is the Canadian Net-Zero Energy Home Coalition. A net-zero energy home supplies to the grid an annual output of electricity that is equal to the amount of power purchased from the grid. This is a somewhat different concept than Passivhaus, but many of the same design principles could apply.

Rising energy costs, peak oil, greenhouse gas emissions and climate change will demand that we cure our wasteful use of non-renewable resources. The technology exists to build super-efficient buildings achieving dramatic increases in resource productivity and superior air quality and comfort. Although disappointingly behind Europe in energy efficient design of buildings we can turn this into an opportunity to start with already proven and tested techniques and have greater confidence in our own ability to meet the challenge.

We are very much looking forward to one day visiting the first certified Passivhaus in Canada.... on the other hand, it may be ours!

[Comments from K. Klingenberg regarding the availability of superinsulated windows and walls in North America:

Our last passive house was built out of prefabbed panels (see www.e-colab.org) which allowed us to secure quality in the shop, implement details that already take airtightness into account and make it easier on site and best of all, it brought the price down dramatically.For our homes we did only import the very first heat recovery ventilator, after that we found materials and equipment on the local market (We have been using the Canadian Thermotech fiberglass windows. They are very close in performance to the German windows).]