Brett Sichello Design + Residential Home Design and Plans + Commercial Interior Design

Triple Glazed Passive House Windows

A high performance triple glazed window is a critical component required to achieve up to 70% energy savings in a Passive House.

Passive House Window SectionThere are so many window products available that even as a home and building design studio we have to constantly question and re-evaluate windows. Not all windows are created equally so we hope that this article will serve as a guide for what qualities and components to look for when selecting high performance windows suitable for an energy efficient passive house.

Considering windows often account for upwards of 50% of all energy loss through a building envelope, it makes sense to invest in a high performance triple glazed window. By investing in high performance windows it allows a home or building designer to shrink the heating system, improve indoor comfort and take advantage of passive solar heating. All of these are good things because they all lead to the same result, saving you money!

Why are quality windows so important?

Number one, the thermal comfort of the occupants is directly impacted by the quality of the windows in the home or building. Everyone has seen a frosted single pane window in the winter and if you've ever spent any time sitting beside that old, frosted window you know that it is not a comfortable experience. So number one, at the very least, let's agree that a superior quality window will help to keep everyone warm and cozy in those winter months and cooler in the summer.

Number two, to minimize energy loss. Why? Because it saves you money! If you choose a quality window you are taking the right step to design and build a significantly better building envelope for your home or building which results in significant energy savings... $$$.

Why use a Triple Glazed Window vs. a Double Glazed Window?

The BC Building Code along with the other provincial and national building codes require windows to adhere to CAN/CSA-A440 which states that a window must have a thermal resistance lower than 1.8 W/(m².K). This rating is the equivalent of double glazed window with one Low-E coating. However, when compared to a high performance triple glazed window, that rating explains why most homes throughout Canada, and the world for that matter, require a large mechanical system to heat and cool the home due to the amount of energy lost through both the windows and the overall building envelope.

High performance triple glazed windows that meet Passive House certification standards are required to have a thermal resistance lower than 0.80 W/(m².K) for all of the components of the window including the frame, glass and even the spacers and gas in between the panes of glass. This is over double the thermal resistance and performance when compared to a minimum building code rated window. Further to that, direct and indirect solar gains are harvested through the glazing which results in more energy gained through the windows than what is actually lost, even throughout the winter. It is critical for the designer to correctly locate the windows as well as consider shading and summer/winter sun angles but this results in huge energy savings.

Triple Glazed Window Section

Why is Window Frame Design so important in a Passive House window?

What most people don't realize is that the glazing unit which consists of three panes of glass, the spacers and gas in between the panes actually performs better than the frame itself. Therefore, the window frame has to be optimized as much as possible to meet the challenging Passive House thermal resistance requirement of lower than 0.80 W/(m².K). It is the combination of a well designed frame as well as an excellent glazing unit which defines a Passive House quality window.

The rapid escalation of Passive House design strategies in the last couple of years has now brought certified windows that are available in wood, vinyl, aluminum, fibreglass as well as many hybrid systems including aluminum clad wood window frames. They all have unique properties in terms of thermal conductivity, dimensional stability, insulated frames, durability and aesthetics but the critical requirement is that they meet the low thermal resistance requirements.

What other elements are required in a high performance triple glazed passive house window?

High Quality Window Components

Here are the other important components that must be considered when selecting a high quality window:

Passive House Windows Canada

In no particular order, if you are searching for the highest quality windows available in the world then look no further. This is by no means all of the manufacturers and products available as additional manufacturers can also be found using the Passive House Institute's Certified Component Library. Notice a real lack of Canadian manufacturers! That being said, we are aware of a number of Canadian manufacturers that are currently working on products that will be coming to market soon. In the meantime, any of the following suppliers will be happy to supply their products and we have worked with a number of these companies on previous projects.


Brett Sichello Design is Modern Home Design studio specialized in
Passive House and Net-Zero Building Design and Consulting.

Contact Us Today to Discuss your Project at 250.448.4307



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