Acceptable duct leakage and AeroSeal?
New Construction, Climate 6B.
On my drawing I have a requirement that all ducts shall be sealed and leak tested per IRC 2015 N1103.3.3.
The leakage rate specified in N1103.3.4 seems quite large less than or equal to 4 cubic feet per minute per 100 sq ft of conditioned space. For a 2000 sq foot home that’s 80 cubic feet per minute.
What is an acceptable leakage rate? Should I target better than code and if so what is a good target?
The next problem is my installer said the ONLY way to get a sealed HVAC system is to use Aeroseal. He gave me no other options and didn’t discuss the cost. I don’t think he was even aware of the pressure test requirement until he was 50% done with the duct work when I asked him about the sealing and leakage. As far as I can see he has only used mastic on a few connections to the air handler.
The reading I’ve done on Aeroseal indicates it’s not a very cost effective method of sealing ducts and it’s only good for 10 years. It seems it is much better to seal the ducts using mastic during the construction. Considering that most of the duct work is already installed what options do I have? I’m I now forced into using Aeroseal?
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