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European vs. North American Passive Home Standards

November 1, 2021

European vs. North American Passive Home Standards

A passive home is designed for minimal energy use through air tightness, super insulation and design for the passive use of solar energy to heat a home. Before 2011, there was one route to certifying a passive home; through the Passivhaus Institut (PHI) founded in Germany in 1996 by Dr. Wolfgang Feist. This standard set limits on annual heating and cooling demands, as well as annual source energy use. It was a single standard that applied regardless of where a home was being built.

It stands to reason that different geographical locations can have drastically different heating and cooling loads for a given building design. North America alone sees a temperature difference of over 40° from Florida to Alaska on specific days. In North America, it was found that the PHI heating demand standards were extremely hard to meet in areas of North America with extreme cold climates, and the cooling demand standards were extremely hard to meet in regions with very warm, moist climates.

A disagreement arose between some in the North American passive house movement and PHI over whether climate should be taken into account for annual heating and cooling load demands. This is how PHIUS (Passive House Institute U.S.) came to be in 2011. PHIUS eventually set their own standard with what is in practice, a very similar annual source energy standard, while adopting annual heating and cooling loads to climate.

PHIUS took into account the varying climates for where windows and exterior doors would be installed in a home. As the milder climates of Utah have completely different insulation and solar gain requirements than windows and doors installed in the heat of Texas or the cold of many Canadian provinces.

What’s the difference?

For Passivhaus Certification, a building must meet the following criteria:

  • an infiltration rate of 0.60 air changes per hour at 50 Pascals, or less
  • a maximum annual heating energy use of 15 kWh per square meter (4,755 BTU per square foot)
  • a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot)
  • maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot)

For PHIUS Certification a building must meet the following criteria:

  • Air infiltration: 0.05 cubic feet per minute per square foot of a building envelope area at 50 Pascals; 0.08 cubic feet per minute, per square foot of a building envelope area at 75 Pascals
  • Peak and annual heating and cooling loads are climate specific to take into account the vast difference between locations (for example, Florida and Manitoba would have drastically different heating and cooling requirements)
  • Source energy limits are based on the number of occupants of the home instead of floor area.
  • As you can see, the Passivhaus Institut standards become difficult to meet in extreme heating or cooling demand climates.

Regardless of whether you choose to build to either standard, or you are simply following passive house principles and are not interested in certifying, Access will help you specify the proper windows for your project.


The Ratings

Windows and doors are rated differently in North America than they are in Europe. European glass is modelled at 0° Celsius and North American glass is modelled at -19° Celsius. Furthermore, Europe uses the EN673 standard, and North America uses the ISO15099 standard. The former is more optimistic, and the latter is a far more detailed and rigorous model. This is important information to consider when you are considering imported windows from Europe. The performance numbers may look great when they are being modelled for the milder climates but when you put them into a colder climate they may well not perform as well. North American whole window assemblies are also physically tested to verify the models whereas the European windows are not.

At Access Window and Door Design Centre, we only want the best for our customers. We have always held our products to a higher standard than any certification program. Therefore, we put all of our products through vigorous testing specific for the North American climate zones and we ensure to use materials like our RAU-FIPRO materials that can withstand even the most extreme weather fluctuations. Our products have proven to endure even the extremely harsh climate of Manitoba, where temperature fluctuations of 80°C can be seen from winter to summer. We believe our products are not only aesthetically pleasing but can be better for your home, better for your health and better for the environment.

If you have any questions about our windows or doors, please feel free to contact us!