What’s Passivhaus?

Passivhaus is the most rigorous building efficiency standard in the world.  Houses built to the standard use over 90% less energy to heat and cool than current modern construction.   Introduced to the world fifteen years ago, there are now tens of thousands of Passivhaus houses in Europe… but fewer than two dozen in the United States.

So, what does the standard exactly call for?

  • a total heating & cooling demand of <15 kWh/m2/yr (4.7 kBtu/ft2/yr)
  • total primary energy of <120 kWh/m2/yr (38 kBtu/ft2/yr)
  • airtightness 0.6 ACH@50 Pa or less

The numbers are meaningless in a vacuum, so here’s an example of what the Passivhaus Institut mandate entails vs what current code calls for.

Standard IRC Code Energy Star PassivHaus
ACH/50 (air tightness) 7 4 .6

 

These are huge differences – a PassivHaus is as much as 11 times more airtight than a conventionally designed and built home. Similar numbers exist in terms of energy consumption as PassivHaus construction calls for about 10% of the energy of a conventional home.

What’s the secret?  The secret is, there is no secret.  There is no magic material, just good design and meticulous construction.