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.
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.
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.
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.