Which Windows to Choose for a Passive House? A Guide to the Best Solutions

Quick overview of passive houses

To get Passive House certification, a building has to meet some pretty strict energy efficiency standards. Passive House Institute US (Phius) makes sure that homes follow specific guidelines for:

• airtightness,
• heating and cooling,
• overall energy use.

An important part of passive houses is the windows, which need to meet specific passive house requirements.

Passive windows started in Europe

The Passive House standard was developed by the Passive House Institute in Germany, which is why European windows are now leading products worldwide, offering excellent energy efficiency that meets the strictest German requirements.

German institute as a passive window global leader

Passive windows are crucial for buildings certified by the Passive House Institute from Germany and the Passive House Institute in the U.S.

You must know that European passive standards are even stricter than American ones. That’s why, if some windows get certified in Germany, you can be sure they will also pass in the U.S.

U-Factor and passive specifications

When choosing windows for a Passive House in the Northeastern U.S., the key metric is the U-Factor of the whole window which measures how much heat a window lets escape. To meet Passive House standards in these colder climates, the overall U Value of the window should be less than 0.15.

This is typically achieved with triple-glazed windows featuring low-e (low emissivity) coatings. For the glass itself (the Ug), you’ll want it to be around 0.5 to 0.7 W/m²K, ensuring that very little heat escapes through the glass.

However, the frame is just as important as the glass. In the North East, where the cold can easily penetrate poorly insulated materials, high-performance frames made from PVC with added insulation are critical to prevent heat loss through thermal bridges—those weak spots where heat can escape.

For a Passive House in the North East, focus on triple glazing with a U-Factor below 0.15, low-e coatings, and well-insulated frames.

Cortizo COR 80 aluminum windows are one of the European thermally broken windows that features U-Factor 0.15 Btu/h·ft2·F

Passive windows from Europe

As with all windows, you can buy them locally in the U.S. or import them from Europe, saving up to 4 times the cost.

To compare window prices from your local vendor with prices of European windows, check the price lists here.

You can apply for certification of your selected windows through the Phius Institute. You can choose between windows that are already in the Phius Certified Product Database or those that are not.

In the second case we reccomend sourcing a window that is already certified in German PHI. It gives it a big chance to gain US certification without problems, because those windows offer great thermal and airtight parameters.

For the certification procedure, you will need the following data, among other things:

• U-value of frames
• U-value of glass
• U-value of the whole window (U-Factor)

Salamander bluEvolution 82 windows are certified at American Phius

The price for 36 x 60″ triple-pane tilt turn window starts from 266 USD