Canada’s Greenest Home Blog #2
One of the key underlying questions about green and sustainable building is: How does one know if a building is really any greener or more sustainable than a typical home?
Quite a number of ratings systems have developed over the past decade to try and help both builders and prospective building owners quantify claims of greenness and sustainability.
At the start of a project like Canada’s Greenest Home, it was important for us to look at all of the various rating systems and select one (or more) that match our goals. As with all things, not all green building rating systems are created equal, nor are many of them even intended to measure the same kinds of performance.
Energy Efficiency
Some programs are designed specifically to rate the energy efficiency of a building and don’t take any other metrics into account. These energy efficiency programs concentrate on higher levels of insulation, better windows, better air control and ventilation systems that recover heat from exhaust air. Lighting and appliance loads are also addressed in most of these programs, with the intent of lowering overall energy usage in the home.
The EnerGuide for New Homes program (from Natural Resources Canada) is now used to establish baseline performance for new residential construction in Canada. EnerGuide provides a score between 1-100, with code approved buildings receiving average scores of 65-72, homes with some efficiency upgrades receiving 73-79 and energy efficient homes scoring above 80. As of January 1, 2012, all new homes in Ontario must be shown to be capable of obtaining an EnerGuide score of 80, so our Canada’s Greenest Home project must provide documentation to the building department from a qualified energy auditor showing that it achieves the minimum of 80. The R-2000 program was a means of achieving an EnerGuide 80, and now that this is the new code minimum the program becomes less relevant. For the Canada’s Greenest Home project, we’re expecting an EnerGuide score in the high 80s or low 90s.
Energy Star for Homes is supported in Canada by Natural Resources Canada. The actual building guidelines and performance targets are very similar to EnerGuide 80 standards. To qualify for Energy Star labeling, a licensed Energy Star builder must build the home, and all the appliances and mechanical systems must be Energy Star rated. We will not be pursuing this certification, though the building will easily meet the requirements.
In the US, the Build America program aims at whole-house energy savings goals of 30% to 50%. We’ve referenced a lot of Build America documents and see a lot of value in the approach, but will not be following this program.
Passive House standards are the most stringent of the energy ratings. In order to be certified as a Passive House, a home must use no more than 15 kWh/m² per year (4746 btu/ft² per year), which can be as much as a 90% reduction from conventional homes. Air infiltration must be at or below 0.6 air changes per hour, also a dramatic reduction from conventional standards. While the term Passive House may suggest homes that don’t have any active mechanical systems, they do require active heating and ventilation systems. However, these systems can be much smaller and more efficient because of the minimal requirements.
We are considering trying to achieve the Passive House standard with Canada’s Greenest Home. A licensed Passive House consultant (Ross Elliott of HomeSol) will be reviewing the plans. We are already including high levels of insulation, an extensive air-tightness strategy and triple-pane windows, which should bring us close to meeting Passive House requirements. We will see what costs and materials will be required to get to Passive House and then decide whether or not we feel there is value in pushing to meet that mark.
Healthy Homes
At Endeavour, we feel there is flawed logic in creating an energy-efficient home that is not a healthy place to live. It is possible to build an entire home without introducing known toxins, and why this isn’t a basic demand from all homeowners is a mystery. Canada’s Greenest Home will use the Standard of Building Biology Testing Methods to assess our attempts to make this home the healthiest environment possible.
Whole Building Systems
More advanced rating systems consider all aspects of the home when assessing its environmental impacts. There are many “whole house” rating systems, some regional and some offered across North America. Most offer a very similar approach. A number of different categories – usually encompassing site/location, energy efficiency, building materials, indoor air quality, water conservation and innovation – are considered, and a number of points are available in each category. Designers and builders achieve points by meeting the criteria in the standard and are awarded certification at the end of the process depending on the number of points attained.
LEED for Homes is the most widely recognized of these programs, and the only one that seems to have achieved mainstream recognition. Having built a LEED Platinum home, Endeavour’s instructors are familiar with this program, and are certain that Canada’s Greenest Home will exceed this standard. However, we are unlikely to pursue LEED certification with this project. While we appreciate the substantial progress made in green building by the adoption of LEED and similar standards (Green Globes, BuiltGreen, GreenHouse, Earth Advantage and many more), our experience with LEED Platinum was that it did not inform or challenge our practices. As builders who have been pursuing high standards of sustainability our entire careers, LEED and similar programs only give us the opportunity to “put a check in the box” for things we already do and leave much of what we do unrecognized. These programs are wonderful for bringing conventional builders onto a greener path and give owners an important means to ensure that a third party is guaranteeing any claims of greenness.
The Living Building Challenge is a sustainable building rating system that we are very excited to engage with for this project. It goes well beyond the other programs and requires a completely different way of thinking about buildings. In each of the seven categories addressed, the Living Building Challenge expects an uncompromising commitment to meeting sustainable goals. It is not a prescriptive or checklist approach, but encourages designers to use the most appropriate regional techniques and materials to meet the philosophical challenge of making buildings that are good citizens of the planet.
Meeting the Living Building Challenge will definitely push our design and build teams to find ways to ensure that our water is collected and treated on site, that our waste is treated on site, that we produce as much power as we use, that we don’t use any fossil fuel combustion, that we provide space to grow food, don’t use any toxic materials and source our materials locally.
It is a challenge we are excited to meet, and we’ll share the whole process on this blog!
