Passive House design strategies are in high demand across the nation
By NATALIE LEONARD
Modern residential construction is governed by building codes that prescribe and describe the rules and objectives governing all new building.
Early North American building codes incorporated best practices taken from builders of the day. Over the decades, codes were renovated in response to builder input, evolving buyer preferences, and to incorporate new technologies and respond to evolving health and safety requirements.
For the early builders, their best practice became common practice and then code, which resulted in safe, reliable, and affordable housing across North America.
Today builders are facing a new and daunting challenge: how to modify homebuilding practice in response to the changing climate. While the transportation and manufacturing sectors have already made significant improvements in energy efficiency, North American buildings have not, still accounting for 50 percent of all energy used.
If we accept that human activity contributes to climate change and that too often that change is destructive, then we must also accept that the way we currently build homes contributes to degrading the environment.
Governments and the public are demanding low-carbon solutions of the building sector and builders must respond. Among the many initiatives to reduce household energy consumption is Net Zero construction using Passive House Design.
A description of Net Zero Passive House Design should begin by defining the terms:
Net Zero is defined in a number of ways: A useful definition says: “A site ZEB (Zero Energy Building) produces at least as much renewable energy as it uses in a year, when accounted for at the site”.
“Passive House describes a set of design principles and defined boundary conditions that— if applied holistically—lead to a building that remains comfortable with only minimal active heating or cooling during extreme climate conditions.”
A Net Zero house is not necessarily built using Passive House Design, and a Passive House is not necessarily Net Zero. Net Zero is a calculation, one that ensures site energy supply and demand are in balance. Passive House Design results in ultra-low heating-energy demand and that provides an excellent foundation for any Net Zero project.
Given its much lower energy demand, a Passive House provides a practical way to balance the Net Zero equation at modest cost: construction costs may increase five to 15 percent over code-built alternatives, but Passive Houses achieve a 75-90 percent reduction in heating costs, with annual heating bills as low as $150.00. The reduced demand for on-site energy production means fewer solar-voltaic panels are needed to reach Net Zero. Net-Metering grid tie-in eliminates the need for batteries and greatly simplifies power management. The result is a much less expensive power generation system that can be amortized in five-to-twelve years, depending on local costs and availability of efficiency incentives.
Net Zero Passive House Design gives builders unique advantages in the marketplace by allowing them to offer customers:
- Significant reductions in heating costs over conventional code-built homes;
- Reduced carbon footprint;
- Superior indoor comfort – the bright, draft free and consistently warm spaces are what owners most love about their Passive House;
- Exceptionally quiet spaces that are isolated from outside noise even during storms;
- Less complex operational and maintenance requirements due to simpler mechanical systems;
- Comfortable conditioned fresh air in the living spaces through the use of high-quality ventilation equipment;
- Increased safety and security during storms – even without power for weeks a Passive House will maintain temperatures above 10C.
Building Net Zero Passive Homes is also good for the community. Much of a project uses locally sourced materials and relies more on builder skills and local labour and less on imported technology. Using fewer imported materials also means a smaller transportation carbon footprint.
Many homebuyers today want the quality, comfort, and energy savings that come with Passive House Design, and they want the carbon emissions reductions that come with Net Zero technologies. They also want lower energy costs and increased energy security, two goals that are especially important to young cost-conscious families and seniors needing to manage fixed assets. Net Zero Passive House Design that uses modest on-site, grid-tied, electrical power generation, is a simple and practical path to reach these objectives in most locations and for most climates.
Natalie Leonard is the first Certified Passive House Consultant licensed to deliver the Certified Passive House Builder training in Canada. As an engineer and the President of Passive Design Solutions, she has worked on over 100 Passive House projects that are net-zero ready and provided support to 30+ builders on their first Passive House projects.