The first time I visited one of Kyle Stumpenhorse’s (RR Buildings) jobsites was in December of 2022. I made the trip to Illinois to blower door test one of Kyle’s Barndominium projects, the project he calls “Building a Barndominium”. The barndo we tested was post and frame construction using closed cell spray foam (CCSF) as both the insulation and air sealing for the project. The home tested very well, 0.41 ACH50.
I got to know Kyle a little on that trip, I was very impressed by his attention to detail and willingness to learn. He pushes himself to do better on every new build. I wasn’t surprised to find out his next project he was planning on using Rockwool insulation. He also had a goal, beat the blower door score of the project using closed cell spray foam as the air barrier. Could it be done?
Recently, I’ve been on a few energy audits and assessments where the homes were built or remodeled in the late 1990’s and early 2000’s. Electricians working in those times were installing the traditional recessed light fixtures, also known as recessed cans or pot lights. This type of lighting fixture usually doesn’t have any issues when installed inside the air and thermal boundaries of the building envelope but can be very problematic when they end up displacing insulation and interrupting the continuity of the air control layer. I’m going to discuss the pros and cons of this type of lighting as well as how we can improve the performance of a home that has existing recessed cans.
When conducting a blower door test, one of the ways we express the findings is with air changes per hour at 50 Pascals (ACH50). As an example, a new home is blower door tested and found to be 2.75 ACH50, this means the entire volume of air inside the home is exchanging with the outside air 2.75 time per hour at the test pressure of 50 Pascals. When discussing blower door testing with builders and homeowners, it can be hard for them to relate to the ACH50 number other than they know the home needs to be less than a certain level of air tightness to meet current code requirements. Expressing the tightness as natural air leakage can sometimes be helpful. How can we calculate the natural air change rate? Well, there’s a formula:
Several of the posts on my blog were first published on the website Green Building Advisor. I’ve enjoyed writing for them, but my hope has been to get an article in their sister publication, Fine Homebuilding Magazine. In issue #304, December 2021/January 2022, that finally happened. Funny thing is, I didn’t get just one article published, I have two plus a tool review, oh, and I’m on the cover.
Air leaking into a home (infiltration) or out of a home (exfiltration) happens naturally in every home, new or old. No matter how much air sealing is performed, we just can’t make them completely air tight. I’ve tested some new homes that were very tight, .33 ACH50, (anything under 1 ACH50 is very good) and I’ve also tested many older ones that aren’t so tight, we can use my 1952 Cape as an example, 9.71 ACH50. In this post, I’m going to discuss how to manually calculate the cost of the air leakage and examine what we can do with that number. Continue reading “Energy Audit-Calculating the Cost of a Home’s Air Leaks”