This article is specifically about the failures of some Habitat for Humanity houses that were going for Energy Star certification recently, but the problems they had are ones not unique to Habitat for Humanity. In fact, this is a problem that occurs with surprising frequency in homes aiming for certification of the Energy Star’s version 3 program. One of the problems happens to be bath fans. Energy Star Version 3 requires that bath fans be capable of exhausting at least 50 cubic feet per minute (cfm) of air, and many builders are discovering that bath fans advertised as 50 cfm are not passing the test; 110 cfm fans aren’t necessarily passing either.
Read the full article here: A Failure that Stalls the Certification of Many Energy Star Homes