We recently did a blower door test on a Xyla in northern New Hampshire to measure its air tightness—i.e., how “leaky” it was. The result was .38ACH@50 pa, which is well under the rigorous Passive House standard of .6 and almost seven times as tight as the strictest building code.
“ACH” stands for air changes per hour…how many times the inside air is replaced by outside air in an hour. “50 pa” stands for the pressure used during the test and roughly equals the pressure of a 20 mph wind. The lower the air changes per hour, the more airtight a house is.
While most of us understand the importance of the R-value of insulation for energy efficiency, minimizing air infiltration is just as important. (more…)