The Sea to Sky Forestry Centre will be built to meet or exceed the Passive Building Standards set out by the BCTF. We are committed to showcasing how energy efficient buildings, and new technologies are supported by the timber industry. Some advantages of passive buildings include:
- Energy Savings of 80-90% compared to conventional construction in Canada.
- Consistent Temperatures. Room temperature does not depend on air temperature, but also from the surrounding wall surface temperatures. Thanks to very good thermal insulation, the difference between air temperature and wall surfaces and windows is very small, which contributes to a pleasant sensation of warmth in all rooms.
- Environmentally Friendly Construction. Energy efficient passive buildings have low power consumption and less negative impact on the environment. Reduction or elimination of burning fossil fuels such as coal, oil and natural gas by energy passive buildings is not only important in terms of reducing the increased greenhouse effect and climate change, but also in terms of taking responsibility for the depletion of non-renewable sources of energy to future generations.
Use of natural materials, further develops the concept of the passive buildings. Passive buildings use natural building materials such as insulation from recycled cellulose, wood components, and clay plaster.
- Air Quality. Passive buildings are tightly sealed against leaks causing drafts. Ventilation units brings enough fresh air to ventilate the building. This system is advantageous, especially in winter when ventilation eliminates the need for open windows. The ventilation is fitted with a pollen filter, helping to maintain air quality which allergy sufferers especially welcome. Humidity in the building is maintained in the range of 30 to 60%.
- Solar Heating. Passive buildings are designed to make use of the Sun as a source of heating. Design and placement of the windows ensures that sunlight is used to provide a comfortable environment year round. Use of shades and the ventilation system ensures that the building remains at a constant temperature even on the hottest summer days and coldest winter months.
- High Quality Construction. To ensure the building meets the standards of a passive building high quality materials and precise construction methods are used throughout the building. The initial investment may be 10-20% greater than standard construction practices, but quickly pay for themselves due to lower energy consumption and higher building durability.
The building will be built using the following design fundamentals set out by the BCTF.
Efficient Building Shape
Since the amount of heat loss from any building envelope is proportional to its surface area, the building’s surface area must be minimized to achieve exceptional energy efficiency. Passive Building designers use a ratio known as the ‘Shape Factor’ to assess buildings, this being the ratio of the building’s surface area divided by its volume. So buildings with sprawling designs, exposed floors, heated garages etc. have higher shape factors, and will therefore experience higher heat losses, even if their floor areas are identical.
Passive solar gains normally form an important component of the heating requirements in a Passive Building. In most regions of Canada high solar gains though south-facing glazing are potentially available and need to be utilized through appropriate design. At the same time, glazing on northern facades should be minimized. Both winter and summer shading performance, as well as year-round comfort design requirements are determined in detail using the Passive House design software (PHPP).
The insulation levels required for any building to achieve Passive Building performance must be determined by modeling the building using the PHPP software and relevant climate data.
Depending on the climate zone, houses built in Canada will likely need between three and seven times better insulation performance than that provided by current national and provincial Building Codes, in order to achieve Passive Building performance. The designer must ensure complete insulation coverage for all parts of the building shell (i.e. thermal bridge-free design).
As the thermally weakest part of a building envelope, windows are a critical component, often representing 50% of all heat losses in a building. The quality of the windows is also critical to interior comfort, and in a Passive Building the interior glazing and frame surfaces need to remain warm enough on cold nights to minimize interior cold spots and downdrafts. In all parts of Canada triple glazing is essential to achieve this, using two low-e coatings and argon (or krypton) gas fill, as well as insulated spacers. It’s also critical that window frames are insulated. Most windows currently sold in Canada meet few if any of these requirements.
Passive Buildings must achieve very high levels of airtightness compared to conventional construction, in order to minimize heat loss from air infiltration, and also to protect the building structure against possible moisture damage.
Ventilation with Heat Recovery
All Passive Buildings include a ventilation system which provides excellent indoor air quality and which has exceptional heat recovery performance.
Ventilation Air Pre-heating
A simple and inexpensive geothermal heat exchanger is often incorporated into the Passive Building heat recovery ventilation system, which allows for pre-heating of the cold incoming airstream and ensures that the HRV unit can be kept frost-free without the need for energy-intensive defrosting. Such systems can also provide some active cooling and dehumidification during summer.
Thermal Bridge-Free Construction
In order to certify a Passive Building, the designer must demonstrate that all parts of the building fulfill a strict thermal bridge criterion. In practice, Passive Building designers have developed a large number of appropriate thermal bridge-free construction solutions, and many of these are presented in CanPHI’s training course. Significant thermal bridging is found throughout all building envelopes in contemporary Canadian construction