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High-performance windows provide views, connections to the outdoors, and even a means of emergency escape. In addition, they can make a home more energy efficiency by capturing passive solar heat gain and daylight. How much depends on the design of the building and the orientation of the windows. And on the windows. Even with long, cold winters, a high-performance window can bring in more heat by solar gain than it loses. However, conventional "code minimum" windows will typically lose far more heat than they will harvest. So, for a Passive House, careful window selection is essential.

And there is another reason windows bear extra scrutiny: most windows do not insulate nearly as well as the exterior wall of even a conventional, non-Passive House building. However, windows vary greatly in their thermal performance. The highest-performance windows available in North America may insulate up to 4 times better than the worst-performing window allowed by building codes.

And this is not important only in winter. Insulation is also important in summer. Just as poor performance windows transfer far more heat out in winter than a Passive House window, the same poor performer allows more heat to invade your home on a hot summer day than a super-insulating window. Thus, these windows can reduce your air conditioning.

A simple, but often overlooked important quality of a high performance window is to be airtight when closed. Just as with the rest of the building enclosure, windows must not leak warm air out of the home in winter or hot outdoor air into the home in summer. Thus, all "operable" (opening) high-performance windows should have multiple, durable, continuous seals and multi-point locking mechanisms to ensure they do not leak air when closed.

At the same time, windows can transmit a large quantity of heat through conduction. You feel this conduction if you put your hand on the inside of a window on a cold winter day and it feels cold to the touch. It shouldn’t.

The inside surface of a high-performance window feels about the same temperature as the inner surface of your exterior walls on a cold day. Try this test on your windows!

High-performance “Passive House” windows insulate far better than conventional windows by using a combination of technologies including low-emissivity coatings on the glass which are invisible to the human eye but dramatically reduce heat transfer by radiation; advanced thermally isolating spacers between the layers of glass at the edges of the panes of glass; three and four layers of glass (“triple” and sometimes “quadruple glazing”) instead of just one or two layers of glass with heavy gases (argon and/or krypton) instead of air trapped in the chambers between the layers of glass to slow heat transfer from convection; and super-insulated frames around the glass.

Today, over 70 European and North American manufacturers supply American and Canadian builders with a wide variety of Passive House windows.

It is easy to get lost in these choices. One way to distinguish windows is by the frames. Windows are made of both glazing and frames. The materials used in the frames influence their thermal performance, not just their appearance. The material and design are also important for durability and aesthetics.

All of the Passive House windows available in North America are listed on this page, but if you have a particular frame in mind, for example you must have wooden frames, then you’ll save time going directly to the Wood Frames page.

Another way to distinguish windows is by where they are manufactured. Many companies in both Canada and the US make high-performance windows, but Europe is home to hundreds of high-performance window manufacturers.

Europe offers not only high performance and quality, but often low prices and excellent service and support; however, distance from the manufacture can affect delivery costs, order lead time, delivery time, potential transit delays, and time/ease for service and replacement parts. Fortunately, most importers have robust supply chains and local support.

Also, there is rarely a bright line between European and local manufacture as many windows are a mix of European-manufactured components assembled in North America.

After each company's name, we include the state, province, or country of manufacture in (parentheses).

Tanner. Wood frame windows engineered and built in Europe. Aluminum cladding option. Complete line incls. historic appearance Brooklyn Double Hung Windows, swissFineLine hidden frame windows. Triple glazing, warm edge spacers, low-e coatings, gas fills, triple seals, multi-point locks, multiple drainage layers.