Passive building achieves energy efficiency primarily through an airtight envelope (the physical structures like walls, roofs, and windows that separate the exterior and interior of a building). Energy modeling is done to determine the energy performance of both the whole building and its individual elements which optimizes the building's performance. Here are the main factors that contribute to a passive house:
1. Proper Insulation: All edges, corners, connections and penetrations must be planned with special care in order to meet the building's design requirements.
2. Air Tightness: Ensuring the least amount of penetrations in a home to be the most air tight.
3. No Thermal Bridges: Escaping heat follows the path of lease resistance. Thermal bridging generally occurs when there's a break in, or penetration of the building envelope (e.g. insulation). Thermal bridges can also be found at:
- The interface between the wall and floor
- The interface between the wall and roof
- Holes in the building envelope for pipes and cables
- Window and door reveals
4. Proper Windows: Usually triple paned windows are installed to help reduce thermal bridging and the loss of heat.
5. Proper Orientation: The home should be placed in such a way so that the sun can heat the house during the Winter and shade is provided in the Summer.
6. Use of a proper Heat Recovery Ventilation (HRV) System: This provides the inside of the home with fresh air without letting the heat out and reduces the number of penetrations in a home.
7. Heating is supplied by your body heat, the sun, your appliances, light bulbs, and even your TV!
Passive homes use up to 85 percent less energy for heating and cooling than the average home. It is also net-zero which means it produces the same amount of energy as it consumes. Although you may be spending more initially on materials and systems that go into your home, you will save money in the long term on your heating bill and help preserve the environment!
If you have any further questions or would like to discuss your next project, please feel free to contact us. For more information regarding passive house, please visit Passive House Canada.