Canada’s Greenest Home at 136 1/2 James Street, Peterborough

Canada’s Greenest Home is about to go on the market, and as we switch out of construction mode and into the process of selling the home on its merits we figured this is a good time to reflect on whether or not we’ve met our goals.

Not a Competition

We were initially quite hesitant to brand this project as “Canada’s Greenest.” The claim was not made to be boastful or to dismiss the work of other designers and builders who have made remarkably green homes. The sustainable building community is very “open source” and cooperative, and definitely not competitive. But we were very interested in pushing as many boundaries as possible with this project, to challenge ourselves as designers and builders to make the very best house possible, going beyond what has been done previously.

Our Goals

We had a very well defined set of goals going into this project, and the sum of these goals, we felt, would result in the greenest home in the country. Here is our self-graded report card:

Extremely high energy efficiency

• The annual heating bill for the home, as determined by energy auditor Ross Elliott of Homesol Building Solutions, will be around $325 annually.
• The home will have net zero energy use if the occupants have “average” power usage habits, and the photovoltaic panels will provide an income for the homeowners.
• We achieved a very high degree of air tightness, with the final test showing 0.63 ACH/50 (air changes per hour at a 50 Pascal pressure differential).
• An Energy Recovery Ventilator (ERV) supplies fresh, filtered air with minimal losses of heat and moisture from the building.
• A complete energy monitoring system with central touch-screen display will assist the owners in meeting their own energy consumption targets. A smart phone can monitor the system from anywhere in the world.

Extremely high indoor air quality

• Every finish and surface in the home meets the highest standards for being chemical free and non-toxic. Achieving this level of non-toxicity was a great challenge, and one we’re proud to have met.
• The air handling system has the best filtration system available, and the owner can control fresh air exchange with simple controls.
• Occupants with chemical sensitivities should find the home to be a very welcoming environment.
  

  Living room with south-facing windows and clay plaster walls

All materials manufactured and sourced as locally as possible

• There are many green building products available in other markets (Europe, in particular, leads Canada in this way), but we wanted to avoid importing solutions and meet our targets using only materials from within a 250km radius. For all the major components of the building, we were able to achieve this goal. This keeps transportation energy costs and impacts minimal.
• The market makes achieving this goal very difficult. Outsourcing to less expensive labour markets means that some categories of products are no longer manufactured in Canada, or even in North America.

Very low embodied energy materials

• We chose materials with the lowest possible harvesting and manufacturing impacts. By choosing materials like straw bale walls from NatureBuilt Walls and recycled cellulose instead of petrochemical foam insulation, we are able to greatly reduce environmental impacts to a fraction of a conventionally-built home’s footprint.

Very low water use, with the potential to be water self-sufficient

• The rainwater collection and filtration system is designed to allow the homeowner to be water-independent. Connection to the municipal water service gives the homeowner the choice to use rainwater for all or just selected uses.
• All plumbing fixtures in the home have the lowest possible water usage rates.
• Composting toilets use 0.1 liters per flush, rather than the industry best 4.0 liters per flush.

No sewage output

• A complete composting toilet system is one of the most distinguishing features of this home. By eliminating sewage output, the home dramatically lowers its environmental impacts, and by creating useful compost the toilet actually becomes a generative rather than a destructive feature.
• The foam flush toilets provide the homeowner with a very low maintenance and “normal” toilet experience.
• The home sends its grey water to the municipal waste water system rather than dealing with it on site. This was our one major area of “compromise,” with regulations, cost and practicality leading us to decide that the small amount of relatively clean water output would go to sewer.

Zero fossil fuel usage

• An air source heat pump (ASHP) provides heating and cooling with no fossil fuel use.
• Solar panels provide all of the home’s electricity needs. When the solar power is not available, a contract with Bullfrog Power ensures renewable energy is still meeting the home’s needs.

Very low construction waste

• By choosing low-waste building materials and carefully re-using, re-purposing, sorting and weighing our leftovers, we were able to send only 852 lbs to landfill, versus 10,000 lbs for an average home of the same size!

Make a Reproducible Home

• We did not want this home to be a “one-off” specialty home. Any contractor or homeowner can reproduce the results of this home with materials and products that are off-the-shelf.
• We intentionally did not choose materials or systems that would require skills, sourcing or maintenance that are outside the scope of any builder or homeowner.

Make a Home with “Street Appeal”

• While aesthetics are a highly personal matter, we wanted to create a home that fit into an existing neighbourhood. The exterior is intended to be attractive without being “showy.”
• The interior finishes are intended to bring a natural building slant to contemporary design, mixing clean lines and open spaces with natural materials and surfaces. Retraining and retooling is not required to build a home like this.
  

  Clay paint on a prefabricated straw bale wall

High educational value

• Endeavour Centre students, who will hopefully take what they learned into the marketplace and assist with building more homes like this one, built the home.
• Our construction blog has attempted to document the process of building the home, sharing our experiences, sources and lessons learned.
• Open houses and post-construction documentation will make this home as open source as possible.

Prove that the market will support green building

• The home was funded by a private investor as a “spec home,” with no government grants or other incentives.
• Placing the house on the open market will hopefully show other builders that there is an appetite for homes of this type. We believe that the market is changing and that owners are willing to invest in a home that has very low operating costs and a high degree of resilience, and which makes their health and well being a priority.

Guidelines and Criteria

We used two green building rating programs to help guide us. LEED for Homes offers mainstream builders an excellent tool for measuring their environmental performance and reaching for higher targets. We aimed to exceed the requirements to meet the LEED Platinum standard, and are well on our way to being certified with a points score well in excess of the Platinum requirements.

The Living Building Challenge is the most stringent construction standard we were able to find, and within its guidelines we found plenty of inspiration. In following the Living Building Challenge we definitely stretched our abilities and understanding and elevated our practice. Certification under the LBC can only happen after one year of occupation, so it will be up to the homeowners to continue to meet the challenge.

No Prescribed Solutions

Despite following two great standards, there is no one-size-fits-all solution to building green. We deviated from some recommendations and requirements of both programs in order to pursue solutions we felt were more appropriate for this project.

We Think We Did It!

There is no reward or prize at the end of a process like this beyond the satisfaction of achieving a professional pinnacle and meeting one’s own very high standards. We anxiously await the buyer who will recognize this achievement and work with us to commission the home in a way that ensures it meets its substantial promise.

As designers and builders, we have learned a tremendous amount from this project, and look forward to applying those lessons to future builds. We also look forward to the day when a home like this is the norm, rather than far exceeding the norms. This type of home building on a large scale would have significant and measurable positive impacts on our environment.

In the province of Ontario in 2002, “1.2 million tones of solid waste were generated from the construction and demolition sector” (Development of Construction and Demolition Waste Recycling in Ontario). A typical home construction project will generate about 8,000 pounds of solid waste per 2,000 square foot home according to the National Association of Home Builders.

The Canada’s Greenest Home project is attempting to seriously limit the amount of material sent to landfill from our construction site. Reuse, recycling and diversion are taken very seriously on this project. To date, we’ve only sent 852 pounds of waste to landfill, and have diverted 3537 pounds to reuse, recycling or other end uses. That is about 10% of the provincial average!

We’ve managed to reduce overall waste to the point where our largest quantity of material going to landfill is floor sweepings! Each time we sweep up inside the building, we pull out any fasteners or recyclable materials before bagging up what’s left. But that dust and debris can weigh a lot, especially after sanding the drywall taping. Our most recent trip to the landfill included 146 pounds of waste, most of which was accumulated floor sweepings. Sawdust, dirt and dust can really add up! We could conceivably bury this material on site, as it’s quite inert. But we wanted to keep an accurate measure of what we “produced” that couldn’t otherwise be reused or recycled.

All material leaving the site was weighed and tracked.

With landfill tipping costs still artificially low (that is, taxpayers subsidize landfill costs for builders), there is little incentive to reduce job site waste. If municipal governments were to charge appropriately for access to landfill, builders would save money by diverting waste to other streams. In the meantime, it’s not difficult to achieve the significant reductions we’ve managed on this project. Placing appropriate bins on site and labelling them well is the biggest step, followed by designating someone on site to manage waste. Buy-in from subcontractors is important too.

Even minimal improvements on conventional building sites could seriously reduce landfill use. We hope this project sets a high bar for what is possible when it comes to construction waste management.

Join us on Saturday, March 9, 10am – 4pm!

Canada’s Greenest Home nears completion

 

Clivus Multrum composting toilet tank

The Clivus Multrum composting toilet is one of the most important systems in Canada’s Greenest Home, and company representative Don Mills came up to Peterborough recently to help us with the fine points of the installation.

As mentioned in a previous post, treating human “waste” as a valuable and important resource instead of allowing it to become a sewage problem is an important step in the move toward more sustainable housing.

Now that our composting toilets are ready to be commissioned, it’s a good time to look at how this particular system works, and why we chose this type of toilet system over others.

There are three basic categories of indoor composting toilets. The first – and by far most simple and affordable – is the bucket toilet. We at Endeavour love the bucket toilet, and recommend it highly for its low cost and effectiveness, but it was not a choice for a spec home! A step up from the bucket toilet (in price and acceptability, if not performance) is the self-contained composter. These toilets feature toilet and compost tray together in one unit. These can be effective in situations where usage is light, but do not have the capacity to handle the daily use of a whole household. In order to try to “speed up” the composting process in these systems, heat is often used to evaporate urine and accelerate the decomposition of the solids. But by getting rid of the urine and making the solids dry and warm, a great deal of the valuable nutrients are wasted.

The final type of composter is the remote chamber style. These toilets have a large storage bin able to accept input from multiple toilets. The Clivus Multrum system is designed to make sure that composting takes place in the best possible environment, resulting in the recycling of the maximum amount of nutrient value.

Illustration of the Clivus Multrum composting system

The main tank for the Clivus Multrum system features a sloped base, with fresh deposits entering at the rear end of the tank and pushing older material forward. Once the system is established, there is a large bed of material in the tank. It is a mixture of solids, toilet paper and wood shavings. In this way, the Clivus system is like many others.

Two aspects really set the Clivus Multrum apart. First, the system captures all of the liquid and makes it accessible as a fertilizer. The urine that is collected has percolated through the composting bed, providing benefits to the solid compost as it passes through and changing in chemistry (to nitrites and nitrates) to become an excellent fertilizer with none of the potentially damaging effects of straight urine. This liquid is collected at the front of the tank and pumped into a separate holding tank. From here, it can be applied directly to gardens and lawns.

The vast majority of valuable nutrients that can be retrieved from human waste are found here, according to Don Mills. Simply diverting and/or evaporating urine is to waste a valuable resource.

The second unique feature of the Clivus toilet is the moistening system. The tank includes a sprayer and controls that mist the compost pile regularly with a small amount of water. This provides the ideal conditions for effective composting: not wet, not dry, but consistently moist. Having provided sufficient nutrients, aeration and moisture, the rich colonies of bacteria, protozoa, rotifers, actinomycetes, fungi, mold, yeast and earthworms can best go to work converting solid waste to useful compost. Dry compost material needs to be removed from the tank about once a year.

When fully functional, the toilet will require monthly attention, to mix in wood shavings. The liquid fertilizer can be pumped directly to gardens or transferred to containers to take it elsewhere.

In an upcoming post, we’ll look at the unique foam flush toilets that are the other unique feature of this system.

March 11-15, 2013

Workshop Instructor(s): George Nez

Workshop Description

Hypar is a shortened version of hyperparabolic, and hypar roofs are one of the most exciting and fascinating architectural developments of the past half-century. This workshop is being taught by George Nez, who developed this system of lightweight roofing, and a rare opportunity to learn from the originator!

Whether used in developing countries as emergency shelter or village homes or used in North American locations with high snow loads, these roof systems use a minimum of structural members and rely on hyperparabolic geometry and fabric with a latex-modified concrete to provide strong, durable and very lightweight roofs for buildings small and large.

George will lead the participants in the design requirements for hypar roofs and the construction of an entire hypar roof. Among the classroom topics covered will be an overview of forms, purposes, calculations,  blackboard geometry, and roof characteristics for various climates and loads. Participants will then frame, stretch fabric and pour the latex cement on a full-sized roof in the workshop.

This is a unique opportunity to learn about a form of construction that defies most conventional thinking about roof structures and could revolutionize your outlook on building design!

Entry Requirements

Open to those with some construction experience

Fee

$550

Maximum class size: 12

January 16, 2013

Workshop Instructor(s): Don Mills
Clivus Multrum

Workshop Description

If you have ever been curious about how a composting toilet works and whether it might work for you, this is the workshop for you!

Clivus Multrum has been manufacturing composting toilet systems for over 30 years, and the company is widely regarded as a world leader in the field. Instructor Brian Barry works for Clivus Multrum and has many years of experience in the field.

This workshop will give an overview of how a composting toilet system works and how to size a system. The main focus of the workshop will be the installation and commissioning of a large M10 Clivus system in a residential setting at Canada’s Greenest Home in Peterborough. Participants will see how the tank is located and installed, how the system is vented and plumbed, and how the liquid pumping and spraying systems are set up. This system uses unique foam-flush toilets, and participants will see how they function and work within the system. Maintenance and upkeep will also be covered.

This workshop will get you familiar with the concept of composting toilets and give you an excellent insight into how a composting toilet can be integrated into a home

Entry Requirements

Open to all

Fee

$55

Maximum class size: 12

The Sierra Legal Defense Fund’s Sewage Report Card for Canada says “Over one trillion liters of primary or untreated sewage is collectively dumped into our waters every year by cities evaluated in this report (of 21 Canadian cities). This volume would cover the entire 7800 kilometer length of the TransCanada Highway to a depth of nearly 20 meters – six stories high.”

With this in mind (and remembering that this statistic is only counting large cities, not smaller cities, towns and individual homes), it is not possible to think about building a so-called “green” home if that home is contributing to this huge environmental problem.

However, unlike many other environmental issues that are complicated and difficult to address, this one can be handled quite simply: We need to compost our own human excrement. The process is not difficult, and there are solutions that range from the simple and inexpensive (see The Humanure Handbook for the $20 solution) to the more expensive – but still remarkably simple and affordable – chamber-style composting toilet as installed in our Canada’s Greenest Home project.

The bottom of the holding tank for the Clivus Multrum M10 composting toilet.

This is the only time you’ll catch me inside the composting toilet tank!

We started the installation of our Clivus Multrum M10 composting toilet unit today, and we’ll cover that installation in more detail as it progresses. But this is not just a “flashy” green addition to the home… we consider this one of the most important features of the home. Not only does it remove this home’s black waste from the atrocious statistic above, but proper composting of human waste creates useful and nutrient-rich soil amendment. At a time when we can ill afford to pollute more fresh water and when soil depletion is a real and growing problem, the composting of human waste provides a win-win solution.

When asked at workshops and public presentations what the one biggest “green” improvement somebody can make to their home, my response is always to move to composting toilets. It’s not a popular answer. We don’t like to think about our own excrement, let alone contemplate dealing with it.

But it’s not as yucky as most people would think. Dealing with a dog’s waste with your hand in a plastic bag is much more visceral and disturbing than dealing with a well-managed composting toilet system, and millions of people have been “trained” to pick up after their dogs. With that in mind, it’s not hard to imagine a future in which turning our own waste into useful compost is socially acceptable and expected.

This woman picks up her dog’s poo with her hand in a plastic bag! Can we be trained to deal with composting toilets?

As those who have followed the progress of Canada’s Greenest Home will know, we are taking the air tightness of this house very seriously. A great deal of thought has gone into ensuring construction details that make it easy to make an air tight enclosure, and just as much effort has gone into work on site to be sure we follow through on those details (much thanks to Graham Wise and our other diligent folders and tapers!).

Siga’s Wigluv tape makes a great seal between the window unit and the air control membrane.

As much as possible, we try to have the air tightness details addressed by building in a way that minimizes breaks in the air control layers and penetrations through these layers. However, there are places where joints and penetrations are impossible to prevent. To date, we’ve done our best to caulk and tape such areas with the best materials available to us.

That pallet of available materials just improved dramatically with our introduction to the line of tapes and membrane materials from Siga. These Swiss products are now imported into Canada by Herrmann’s Timber Frames in Curran, Ontario. As soon as we opened our first roll and began to apply it, we knew that air sealing for us was changed forever!

Siga’s Rissan tape seals the membrane to the electrical box hood.

We are working largely with two products from Siga. The first is their exterior-grade tape, called Wigluv. This tape is outrageously sticky, and the tape material very flexible. We are using the Wigluv to tape our air control layer (a conventional Canadian housewrap) to our windows to provide a seal at this important junction.

The Wigluv takes some learning to apply cleanly, as it is so sticky that any errors in application result in tape stuck to fingers and any other surface that gets in the way! However, we quickly figured out how to fold the tape against the window to provide an excellent seal. Working from bottom to top of the window, we provide positive overlap at each tape seam. The flexibility of the tape means that the odd lump or bump in the application folds down completely, and if the corner is not perfectly ninety degrees, it will bend out of the way of the strapping we put on next. I feel like these will definitely be the most air tight windows we’ve ever installed.

The second product is similar, but meant for indoor applications, and is called Rissan. This tape is flexible enough to be very useful for sealing round holes in membranes, such as plumbing vent stacks and electrical conduits. Equally sticky as the Wigluv, the Rissan bonds to pipes, wires and conduits firmly and provide a great solution to these very hard-to-seal areas of the home. We will use the tape from both sides of the barrier wherever possible to further ensure a tight seal.

Whether or not these tapes have long-term lasting adhesion remains to be seen, but their test results are impressive and they far surpass anything that is widely available in the North American market.

This entire window is now very well sealed and insulated.

For the time being, it’s too bad we have to import these tapes from Europe. Canada used to be a leader in the first wave of air tightness products for homes, but until somebody in North America starts making tapes of this quality, we’ll be using these Siga products to ensure our seams and joints are as air tight as possible.

As a teacher, there is nothing more satisfying than to know that what you have taught has been absorbed, understood and sometimes even improved upon by a student.

Kate and Bernat with their amazing hybrid straw bale house

Jen and I were recently driving to Nova Scotia, and paid a surprise visit to Kate Alvo and Bernat Ferragut who were in our sustainable building program in 2009. They have designed and are close to finishing construction on their home in Port Neuf, Quebec.

They have exemplified the kind of careful planning, thoughtful research and quality building work that all add up to an excellent sustainable building project.

It was wonderful to be able to tour the home a bit ahead of its final completion, as we were still able to see the “guts” of the build. From a beautiful and functional design to the fine details of air sealing to excellent materials selection, this is exactly the kind of home that can make a real difference to our impact on the planet.

Kate and Bernat have, since 2009, run a business called Le Chantier du Bonheur, performing ecological renovations throughout Quebec.

Among the many great ideas and technologies incorporated into their home, the one I was most excited to see was the pellet boiler heating system and the deluxe hot water tank that accompanies it.

The pellet boiler on the left and the triple input hot water tank on the right should make for a very efficient and affordable heating system.

I have long been interested in pellet boiler technology, but have yet to install a system into a building. I see pellets as an excellent fuel source when made with regional waste biomass (as is widely available throughout much of Canada). The pellets burn more cleanly and efficiently than wood stoves or furnaces, and the boiler system allows easy hook up to hydronic heating systems and domestic hot water end uses. A large hopper allows enough pellets to be loaded to ensure long run time capability, so heating with biomass no longer means having to be at home all day to feed the stove.

The water tank has a triple input, allowing water in the same tank to be heated by solar, the pellet boiler and a backup electric resistance heater. The large capacity of the tank takes full advantage of solar input and the pellet boiler, and the inexpensive (to install) electric resistance heater means that the house never goes without heat, even if the boiler runs out of pellets.

The pellet boiler is from Pellmax and the tank from Aqualux. The two units were very affordable, and I’m very glad to be able to find out how they work without always being the first adopter of a new technology!

We wish Kate and Bernat all the best as they finish their home! You can follow their entire project history on their blog.

Among the many challenges involved in meeting the Living Building Challenge standard for Canada’s Greenest Home, one of the biggest was how to heat the home given that the LBC does not accept combustion devices of any kind for any purpose.

The Mitsubishi Zuba heat pump is installed on the exterior of the house.

The heat exchanger and plenum for the interior side of the Zuba.

Our first choice for heating this home was going to be a pellet boiler. Impressed with the efficiency and cost of these systems, we were also aware that a number of local pellet making facilities (including one less than 1km away from the home) meant that our fuel supply could be reliable and entirely based on existing waste biomass in the region.

Once we understood that this combustion option was not feasible (and I’m not sure I agree with the LBC’s reasoning on this point), our focus turned to heat pumps, both ground source and air source. Heat pump technology is a great option, as it is the only heating (and cooling) technology that is more than 100% efficient. With combustion devices, for every unit of fuel input there is slightly less than one unit of heat output (hence the ratings that might state efficiencies in the 90% range). With heat pumps, each unit of energy input (electrical energy, used to drive the pump) there is between 1.5 and 5 units of heat created, meaning that efficiencies can be stated in the 150-500% range.

A heat pump works by circulating a refrigerant with a boiling point that is designed to be in the temperature range expected on the outside of the building. By compressing this gas and forcing it into a gaseous state and then allowing it to return to a liquid state, the refrigerant goes through two phase changes. The heat that is transferred during these phase changes is significant, even though the temperature of the refrigerant is not.

The heat pump cycle explained. The important part to know is that the phase change of the refrigerant releases usable heat, even if the actual temperature of the refrigerant is not “hot”. Image from CMHC

This isn’t magic, and it isn’t even a new technology. Your refrigerator is a heat pump, as is your air conditioner. The premise has been around for decades, but has only recently been applied to heating homes on a large scale in the past decade. The use of heat pumps in cold climates has not been feasible until quite recently, when Mitsubishi introduced their Zuba range of cold climate heat pumps. These units are able to make usable heat at temperatures as low as -30C, making them feasible as the sole heat source for a northern climate home as long as the home is made to be energy efficient.

The heat loss calculation for Canada’s Greenest Home was 22,524 Btuh (British Thermal Units per hour). The Zuba is capable of producing 34,130 Btuh, so it is well within the unit’s capacity to fully heat this home.

As with all heat pumps, the Zuba can run in reverse and be an efficient air conditioning unit in the summertime.

The Zuba has two components. On the exterior of the house there is the heat pump unit. On the interior of the house there is the heat exchanger and the air plenum plus the fan and switchwork for the system. It is connected to conventional ductwork to supply heated air to the whole house.

The Mitsubishi Zuba units are supplied in Ontario by Mitsair. Our system was installed by Crown Heating in Peterborough. Our thanks to both companies for their professional assistance.

The decision to go with an air source heat pump was made largely based on the cost of installation. While a ground source unit offers better efficiencies (especially at colder outdoor temperatures), the cost of installation is quite a bit higher, and the payback on the additional investment is well over a decade. Given our investment in other technologies for this home, we decided in this case that the lower cost of installation and the very good efficiencies for the unit made it the right decision for Canada’s Greenest Home.