Comments on: What Is Pressure? – Understanding Air Leakage

By: Anonymous

Anonymous — Tue, 25 Jan 2011 06:54:47 +0000

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I love, love, love that ad.
I love, love, love your writing.

By: Allison Bailes

Allison Bailes — Tue, 25 Jan 2011 04:29:23 +0000

Jeff, as long as you're
Jeff, as long as you're testing with a 50 Pascal pressure difference every time, I don't think that 'the remaining leaks leak harder.' The only way that would happen is if the house were so leaky at first that you couldn't get to 50 Pa, and as you continued testing, you increased the pressure difference until you got to 50 Pa. I think it's probably just a matter of having sealed up the big, easy to seal leaks, so the remaining area is smaller.

Another home performance contractor once told me, though, that sometimes you could have a 'mad air' thing going on, where you seal up some leaks and make the air angry so it finds new leaks. Fluid dynamics is pretty complex, and there could be some of that going on, but I think it's mainly just the diminishing returns of having sealed up the big stuff already.

By: Jeff DeSart

Jeff DeSart — Mon, 24 Jan 2011 20:02:04 +0000

I have a complicated question
I have a complicated question about pressure. As my team and I seal up a house and perform blower door tests as we go to check our progress, it seems to us that it gets harder and harder to reduce that cfm50 number. We speculate that as we seal up envelope leaks, the remaining leaks leak harder, so that we get reduced returns on the leaks we seal as we seal more leaks.