Passive housing originated in Germany under the name Passivhaus. It is a voluntary standard utilized in architecture and design that focuses on energy efficiency within a building. The goal of Passive House design is to reduce total energy use associated with heating or cooling. In layman’s terms, implementing the Passive House principles can create an eco-friendly home. It is not supplemental to architectural design, but instead a design process that integrates with the architectural design. Passive House is based on a number of key principles; Solar Orientation, Super Insulated Envelopes, High Performance Windows, Thermal Bridge-Free Design, as well as Balanced Ventilation with Heat Recovery. Let’s take an in-depth look at these principles:
1. Solar Orientation
Solar orientation refers to how the glazing along the building's exterior is positioned based on the location of the sunrise and sunset. With Passive House design, all glazing should be located on the Southern-facing side of the building to absorb the sun’s heat energy and warm the interior during the winter months. In the summer, shading or overhangs can be included to provide relief from the sun's rays and keep the interior cool. Locating a building along the East-West axis is ideal. If the building cannot accommodate adequate shading, simply reducing the amount of glazing is a viable option. While solar orientation is one of the first principles of Passive House design, it does not necessarily apply to all structures. Some buildings or spaces don’t require additional heat from the sun, as they are simply warm enough from heat produced by people, activities, or equipment.
2. Super Insulated Envelopes
Insulation is a key aspect of Passive House design. When air is heated to keep the interior comfortable, some heat will be lost as it moves through the envelope, through the process of conduction. Utilizing large quantities of insulation within the building envelope will not only help to reduce heat loss, but will also provide greater acoustic control and improved durability. Optimizing the materials and construction tools used during construction will provide a more sustainable option, compared to relying on electrical and mechanical services. Insulation is most effective when it encapsulates the building uninterrupted by other construction assembly materials; however this is not always possible. When a material bypasses insulation, this causes a thermal bridge, which can significantly reduce the effectiveness of the insulation, especially if the material is conductive. Making insulation as continuous as possible will provide the most efficient building envelope.
3. High Performance Windows and Thermal Bridge-Free Design
Windows in a Passive House building are often triple-pane insulated with air-seals and thermally-broken window frames. While this may sound confusing, these high-performance windows simply allow for solar heat gain and daylight without losing copious amounts of heat, as is the result with traditional design principles. This means that windows are no longer the weakest part of the home. Often, the need for insulating the window frames is completely eliminated. It is essential to avoid all thermal bridging within the design to prevent condensation build-up and heat loss from door and window frames, as well as flooring. Make sure there is careful attention paid to detailing during the design and installation stages.
4. Balanced ventilation with heat recovery
Since Passive House projects are essentially airtight, a ventilation system that brings in fresh air and removes pollutants, odours, CO2, and moisture is essential. Ensuring balanced ventilation within the building includes efficient heat recovery. Low-energy heat recovery ventilation (HRV) systems provide a supply of fresh air throughout the interior, even when windows are closed during the cold winter months. In addition to maintaining a flow of fresh air, efficient HRV systems provide perfect air humidity levels for health conditions all year round without wasting excess heat.
This is simply the beginning of our deep dive into passive housing and all that encompasses this design. Coming up soon is “Passive Housing: What you need to know”, which will look into the benefits of passive housing, as well as the costs, the statistics, and more! Let us know down below if there is anything else you want to learn.
Burrell, E. (2018, June 18). Passivhaus: Solar orientation doesn't matter. or does it? PASSIVHAUS IN PLAIN ENGLISH & MORE. Retrieved April 4, 2022, from https://elrondburrell.com/blog/passivhaus-solar-orientation/
Design, L. I. (n.d.). Passive House 101. Passive House design specialists. Retrieved April 4, 2022, from https://localimpactdesign.ca/passive-house/#:~:text=Passive%20House%20concentrates%20on%20a,from%20the%20hot%20summer%20sun.
Norris, N. (2019, January 1). Five principles of passive house design and construction. Passive House Accelerator. Retrieved April 4, 2022, from https://passivehouseaccelerator.com/articles/five-principles-of-passive-house-design-and-construction