Saturday, August 20, 2011

Products to avoid: attic vent covers

I'm not a big fan of negative talk, but one product that I have seen at a few homes during inspections always gets a mention: attic vent covers. Don't use them.


The theory behind these products is that trapping even a small amount of heat in the unfinished attic space will help lower one's heating bill. That theory may prove to be correct, but the downside can be far more expensive to fix: keeping heat in the attic equal keeping moisture in the attic.

Moisture condenses on colder surfaces--such as roofing nails which penetrate the roof sheathing. The moisture freezes. Then the surface warms up, the ice thaws, and the water drips onto the surface below. Repeat this process for several years, and the consequences can range from moldy insulation to rotten attic structures. The expenses of fixing these issues will far outweigh any utility bill savings that were gained from using vent covers.

Leaving the attic vents open during the winter months helps to remove the moist air. Let them do their job.