Passive House is a voluntary international building standard developed by the Passive House Institute in Darmstadt, Germany. Here’s the institute’s official definition of a passive house:

“A Passive House is a building in which thermal comfort (ISO 7730) can be provided solely by postheating or postcooling of the fresh air flow which is required for good indoor air quality (DIN 1946) – without using recirculated air in addition.”

To meet the standard, a house must use 90 percent less energy for heating and cooling than average buildings. High-performance windows play a vital role in achieving that goal.

The window frame is especially important in passive house construction. Slimmer frames and larger surfaces of glass are preferred because glass performs better thermally than most framing materials. More glass also means more solar heat.

The Passive House standard for windows dictates that “window frames must be well insulated and fitted with low-E glazings filled with argon or krypton to prevent heat transfer. For most cool-temperate climates, this means a U-value of 0.80 W/(m²K) or less, with g-values around 50 percent.”

However, because they’re one of the weakest efficiency links in the entire structure, those window frames must be insulated. Triple and even quadruple low-E glazing and insulated frames might be required in cold climates, while warmer regions could get by with double low-E glazing.

According to Katrin Klingenberg, the co-founder and executive director of the Passive House Institute US (PHIUS), her organization has trained nearly 2,000 professionals in passive house construction standards. Since 2012, PHIUS has certified 120 construction projects, and there are about that many in the pipeline, according to the organization’s website.

According to the Passive House Institute, super-insulated structures have a long history all over the world, from China to Iceland. However, the modern incarnation was born in Europe.

In 1973, researchers at the Technical University of Denmark built what’s widely considered the first zero- or low-energy house. It featured active solar technology. Meanwhile, in North America, the concept of the “super-insulated house” came to the forefront in the 1970s and 1980s. It was influential in the development of low-energy houses and passive houses in Europe.

In 1974, German researchers built a super-insulated experimental house that showed the potential for massive energy savings (a factor of 10 to 20 over standard homes, according to the Passive House Institute).

One of the biggest barriers to achieving a truly passive house in those days was the absence of the high-performance windows we know today. Windows in those early structures were small, or covered with insulation.

DWM Magazine

1 Comment

  1. We started importing and promoting the Tilt & turn System in the early 80’s.
    It is a constant, very hard, educational process; but the American thinking about
    saving Energy is slowly turning. Eurocraft Industries was also the first to Impact-Test
    uPVC windows and doors; but still need to educate contractors, architects and Home- owner about the tremendous advantages of the Tilt & Turn System.
    Hans Severin
    Eurocraft Industries Inc

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