A high performance house design requires a high quality build. We met and exceeded the goal for the mid-build blower door performance check with a measured whole house air leakage of 0.42 ACH50 (.42 whole house air changes per hour at 50 pascals pressure). To meet the Passive House standard, we needed to be at 0.6 ACH50, but that wasn't going to satisfy our highly motivated builder!
Builder Ryan says... "We started at .64 (244cfm) and began fogging and looking for the "big leaks"... after a couple hours of hunting and sealing leaks we managed to reduce the number to 210 cfm. We then looked closer at the basement thinking that the windows may hold some significant potential improvements only to find that the sump basket and the floor drain were leaking drastically compared to anything we found thus far. Ran the test again and this is what we found! .42 ACH ! Success! According to the PHPP output from Tim Delhey Eian at TE Studio, Ltd., this signifies a 10% reduction in the already 90% reduction in heating and cooling load for this house as compared to building code standards."
To offer some additional perspective on the air-tightness results, we have included the summary table below. Do you know how your house performs? We had the blower door test run on our current century-old home, and the number was 7.2 ACH50, that's 7 whole house air changes per hour at 50 Pa, otherwise known as very leaky and drafty. This is even after considerable effort on our part to mitigate leaks and improve energy efficiency over the past 12 years we've lived here. The drastic difference in uncontrolled air diffusion is a big reason our projected yearly energy bill for the new house is over half what we currently pay, despite the square footage more than doubling.
Since the successful blower door test was performed on July 3rd, coincidentally the shared birthday of Julie (homeowner) and Tim (architect), we celebrated with breakfast pastries from Aki's Backstube, the new German-style bakery in NE Minneapolis, brought to us by the Central Avenue revitalization efforts of the Northeast Investment Cooperation. These are just a couple of reasons we love Nordeast!