STAFF WRITER – The Ottawa Construction News Special Feature
Passive House is becoming a more commonly heard reference today. But what is it, what are its benefits and why is it the new standard construction and design should be working toward?
Passive House is a design tool used to create buildings with superior thermal comfort and indoor air quality with low operating costs, capable of conserving up to 90 per cent of the heating or cooling energy used by an average building, says CanPHI West president, Rob Bernhardt.
He says careful design, integrated with a detailed building energy model creates a simple, high quality building envelope, which does most of the work. By focusing on the envelope, complex mechanical heating and cooling systems can be replaced with simple but efficient ventilation and heating. The building envelope ensures stable interior temperatures and a heat recovery ventilation system provides a continuous supply of fresh air throughout.
Despite the name, Bernhardt says the Passive House standard can be applied to any building type; including single family homes, offices, schools and high-rise buildings. “Since the 1980s, we have seen tens of thousands of Passive Houses built around the world, proving the standard works effectively in any climate.”
The most noticeable benefit to most occupants he says is the even, comfortable temperatures in all seasons, with no drafts, cold floors, condensation or summer overheating. “Occupants of a Passive House enjoy thermal comfort all year round, as well as superior indoor air quality from the continual flow of fresh air provided by a heat recovery ventilation system.”
Warm interior surface temperatures and airflow also prevent moisture damage and mould growth that, together with high quality components, minimize maintenance costs. For governments and municipalities, Bernhardt says Passive House provides a meaningful and reliable tool to reduce building energy consumption and achieve greenhouse gas reduction targets.
Designing a Passive House building requires the use of a detailed energy model that enables the architect to make accurate energy calculations using location specific climate data. “Training is essential to design a Passive House and courses are offered across Canada.”
Bernhardt says with the required Passive House training, attention to detail and careful design, anyone can build an affordable Passive House. and, although the choice of high quality components, such as windows, doors and ventilation equipment are still limited in North america, options are expanding rapidly, he says.
“As in any field, those building first projects will encounter a learning curve and must be prepared to get the details right.”
In a high performance building, small design defects can make a big difference to performance, he says. “Experience illustrates almost any team can be successful even on a first project and with limited or no prior Passive House experience, as long as the training is obtained and care is taken.”
Bernhardt says the number of Passive House projects in Canada is growing so rapidly, it is difficult to calculate an accurate number. Many communities, he says, have multiple completed projects, with more in design. “B.C. remains the province with the highest number of projects, but interest is growing quickly in other provinces and we’re continually hearing of new projects from alberta and Saskatchewan to Ontario and Prince Edward Island.”
Bernhardt says the commitments recently made by world leaders in Paris require meaningful improvements in building energy efficiency. “Passive House is a tool that offers an accessible and reliable means of achieving those goals. as building energy efficiency requirements improve, Passive House design will become common as it is simply an application of basic building science principles achieving affordable, yet sustainable, buildings.”
Bernhardt says the Salus Clementine project demonstrates the advantages of Passive House in the social housing sector. “although there is a modest increase in design and construction costs, a well designed Passive House offers the most affordable option for a long term owner, in addition to providing amazing comfort and air quality.”
“The project team for the Salus project has done a tremendous job, not only in delivering the first larger Passive House in the Ottawa region, but in offering information to government, industry and the public about how affordable and sustainable the buildings of the future will be.”
Geo-Energie Inc. represents Ottawa-Salus for the Salus Clementine project, acting as the commissioning authority and consulting engineer for renewable energy issues.
Geo-Energie president, Patrick Lambert, says his company’s role is to ensure, through an established and documented process, that all mechanical and electrical systems operate properly, as designed, and that they have been thoroughly tested before releasing the building. “Passive House requirements bring a whole set of new consideration when designing a building,” he says. “Mechanical systems are influenced by PH requirements. It is a challenging, but highly motivating, project. The project’s team is highly competent and dedicated to make this a success.
Lambert says his company was asked to assess the energy efficiency of the elevator equipment, as per European standard VDI4707. as a Passive House requirement never previously performed in Canada, this presented unique challenges. “No one had the required experience on the project’s team. So we had to learn the procedure and find the metering equipment.”
This kind of trouble-shooting and meeting unexpected challenges has been at the heart of Geo-Energie’s success since its founding in 2004 and subsequent growth to complete more than 600 professional mandates. “Our experience in commissioning came from our renowned expertise in troubleshooting problematic HVaC systems and similar legal expertise we conducted. It led us to offer third party project’s supervision and, eventually, complete commissioning services.”
Presently, the company is providing tailored commissioning services to three other projects in Ottawa (all LEED® qualified) and has completed work on numerous other projects in the area.
For more information, visit http://geo-energie.com.