A smarter attic fan?
In doing retrofit insulation projects, attic ventilation is a topic that frequently arises. And here in coastal Maine, it can be touchy as well. Best practice attic ventilation is soffit to ridge channels, which will allow free flow of air and great year round drying potential. But many homes only have gable vents or less, and soffit to ridge venting may be impossible at worst or impractical at best. We have found that the attics without ventilation may be as dry as those with ventilation, and some with ventilation are quite damp, even after air sealing.
The bottom line: the humid air mass of a coastal New England summer puts a lot of stress on attics (and other enclosed spaces) as temperatures cool in the fall and that air mass can no longer hold as much moisture (and thus carry it away). What can be done to improve a building’s chances against these conditions? I’m thinking mechanical (attic) ventilation may help.
There are plenty of attic fans out there, and in general, they don’t do a lot to help with this. But what would help is a fan with a control module which measures both attic conditions and outside conditions, and turns on only when there is drying potential by increasing the air exchange rate.
So therein lies the question: Does such a product exist? And do we think it would really help?
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