I have reviewed, tested, studied, asked, and analyzed the many facets of whole house air leakage. I am still somewhat unsure what constitutes a respectable level of air leakage to a home. Newer…Continue
"This is definitely worth investigating if you are an air sealer and are forced to use the ACH50 metric.
First look at a 1500 ft2 ranch on a slab at 50'X30' with an 8' ceiling. It has a volume of 12,000 ft3, and a surface area,…"
"Air sealing can also provide an opportunity to reduce contamination from dirty attics and crawlspaces though, but you are right that ventilation is key which is why I think crawlspace fans are a good idea.
"This jives with my experience trying to air seal a very small house - lots of caulk and foam and not much of a result (only a few hundred CFM after several hours of work). Bigger homes seem easier to reduce in my experience."
Do the math on that one - any volume based measure favors big houses because the volume is not what is leaking - the surface area is. A small house has more surface area per ft3 than a big house, so gets penalized. I have measured…"
I'm not sure I follow. Is it because the 2012 IECC does not include the basement area as conditioned space, or that slab houses are viewed as being "leakier" than houses with double the flooring footprint and having a basement,…"
+1 to everything you said. Something to add is that it depends entirely on the metric you use. If you use ACH50 which is becoming the norm where the 2012 IECC is used, you must seal every square foot of envelope on a 1200 ft2 house on a…"
"I have been thinking quite a bit about this topic recently, and the more I think about it the less convinced we are on the right track.
First - blower door tests DO NOT give an indication of air infiltration; they give a slight indication of the…"
"Old homes are not great candidates for ASHRAE standards. It can be achieved with risk. Unless the energy rater understands all the hidden problems associated with the old home in question, air sealing can present some long term health issues with…"
"This doesn't have to be that complicated….
If your goal is to save energy, the answer is always "get it as tight as possible" If your goal is to save energy and assure indoor air quality, the answer is "build tight and…"
"Roy, I have not tested for humidity post-retrofit, but that isn't a bad idea. I do know the crawlspace fan works to dry out the crawlspace; we had a client with a flooded basement and installed a vent fan which dried it right up in a few…"
"Thank you for your input. I am curious if after you complete sealing the rim joists or other areas whether you performed any moisture tests after the sealing to determine the moisture content. Our area does not normally have moisture…"
"I've tackled quite a few air sealing projects on homes built in the 1800's in the Colorado Rockies. They can be quite a challenge to air seal, even at the 10% required by our utility for rebate funds. If the crawlspace is…"
I have reviewed, tested, studied, asked, and analyzed the many facets of whole house air leakage. I am still somewhat unsure what constitutes a respectable level of air leakage to a home. Newer homes built to higher standards are not a problem but when you get into older homes with varying degrees of air leakage depending on when they were built and by whom presents some interesting situations. The recommended rates of leakage on older homes do not present the same situation as new homes as…See More
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