Should I seal my crawl space?
by Carol
(Eatonton GA)
I have been approached by a man who recommends that I seal my crawl space in my 1800 square foot house. Is this a good idea, how much should it cost, and would you recommend it?
Answer from Green Energy Efficient Homes
I recommend sealing a crawlspace if you live in a cold climate and have significant air leakage between the crawlspace and the rest of your house, as well as leakage out the upstairs of your house through drafts, leaky windows and so on. The stack effect in a house with poor air tightness is such that hot air rises to the upstairs and leaks through drafts, which pulls in cold air from below. The more air leakage there is from the crawlspace into the living area and the more leakage from the upper floor, the greater the heat loss you'll experience in cold weather.
Note that sealing your crawlspace may violate local building codes in your area; check with your building permit office.
Given that the climate in Georgia is significantly warmer than my hometown of Toronto, I would be inclined to think long and hard about the benefits of sealing the crawlspace in a Georgia home, versus the costs. If you are wanting to do this because your downstairs floors are cold above the crawlspace, you may be able to address the problem by insulating the floor or indeed the crawlspace exterior walls, without sealing.
I don't expect there is that much energy saving benefit to sealing a crawlspace when it comes to air conditioning. You would be reducing the amount of humidity in the crawlspace, which if there are leaks into the home could reduce humidity in the home itself and therefore the air conditioning burden, but there isn't nearly the savings here you would see on the heating side.
As for cost, I can't comment as I haven't had my own crawlspace sealed, and contractor prices vary vastly from region to region and even neighborhood to neighborhood. My recommendation would be to get several quotes before proceeding, as a contractor who knows he is the only one bidding may jack his price up unreasonably high.
For more information see my main Crawl space heater page.
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