ach50

Meet the Tightest House in the World

Posted on January 31,2015 by ScottG in ach50

A Dillingham, Alaska, couple has claimed a world record for airtightness in a 600-sq. ft. home with 28-in. thick walls and a ceiling rated at R-140. According to the World Record Academy, a blower-door test measured 0.05 air changes per hour at 50 pascals of pressure (ACH50), less than 10% of the very rigorous Passivhaus air-tightness standard of 0.60 ACH50.

What’s a Blower Door Good For?

Posted on January 31,2015 by ab3 in ach50

In last week's blog, I suggested that talking about infiltration rates in terms of air changes per hour isn’t an accurate way to portray air leakage. The problem is that you’re dividing by volume but the leaks happen at the surface. I don’t think ACH50 is going away anytime soon, and I use it myself because everyone else does, even though it’s biased toward larger houses.

Air Leaks Happen at the Surface, Not in the Volume

Posted on January 31,2015 by ab3 in ach50

During the Westford Symposium on Building Science in 2010,* I was watching the tweets from the people who were there. At one point, I saw this one: “@EFL_Guy: ‘Air leaks through surfaces, not volume’ Joe Lstiburek.” I'd been meaning to blog about this issue for a while, so I wrote an article about it. Now, a couple of years later, it's time for a little update.

Green Basics Air Barriers
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