After getting all the windows and doors installed, sealed and caulked tight, it was time to call for the "blower door test". Kristen has mentioned our goal of building a high performance house, and stopping drafts and accidental air leaks (aka: "infiltration" in architect speak) is a critical component of our overall design.
For the test, we set up the blower door tent over our front entryway
, sealed that up tight and cranked up the fan- sucking air out of the house until we had established the industry standard pressure of 50 pascals. Note: to achieve this kind of pressure differential naturally, I've been told that you'd have to have around 50mph winds blowing against your house. [Kristen here, the blower door testing guy told us this...]
We had really good results- with 922 cfm of airflow initially. We walked around the inside of the house and tried to locate any places where I had missed caulking and sealing the sheathing and windows when I was getting the walls framed up and closed in. Surprisingly, a couple of our doors were not locked, and as soon as we did that, they sealed up tighter and we had an even better reading on the fan with 897 cfm.
Our goal of reaching "Passive House" standards translates that cfm into total air changes per hour. The target is 0.6 ACH (Air Changes per Hour), and at the time of this first test, we had hit 1.4 ACH. I'll attach some links for you all to look at if you are interested, but for reference, current code minimum is 7.0 ACH and "energy star" minimums are at around 6.0 ACH.
We might not get down to that German "passive haus" standard, but we'll keep improving. I'll do another blower door test after we get up the sheetrock, and once more after we get the rigid insulation, stucco and siding installed in the summer.
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