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Forums | Environmental Impact | installing fans in crawlspace |
| Author | Message |
mbombeck | Posted - 20 December 2002 10:48    I have a portion of my crawlspace that is slightly damp--about 350 sq. feet. I am thinking about installing a permenant fan in the space to circulate air and keep it dry. What kind of fan should I install? Where do you install it? Do you need a duct to vent the air outside or does the air blow inward into the crawlspace. Any recommendations for fans? Would one fan be enough? Any help would be greatly appreciated. |
path1 | Posted - 3 February 1999 8:52 I have a portion of my crawlspace that is slightly damp--about 350 sq. feet. I am thinking about installing a permenant fan in the space to circulate air and keep it dry. What kind of fan should I install? (An exfaust fan rated for damp locations, check w/ an HVAC contractor) Where do you install it? (Out crawlspace wall) Do you need a duct to vent the air outside or does the air blow inward into the crawlspace. (Duct or at wall) Any recommendations for fans? (No) Would one fan be enough? (Probably) Any help would be greatly appreciated. Homebase Hotline Staff homebase@nahbrc.org 1-800-898-2842 fax 301/249-0305 http://www.nahbrc.org NAHB Research Center 400 Prince George's Blvd. Upper Marlboro, MD 20774 |
dyoungkeit6 | Posted - 24 March 1999 22:20 There was an article in Popular science about 12 years ago that suggested that the crawl space become a plenum for return air toward the forced air furnace. With the furnace forced circulation, the space will dry out without using any extra energy. Return air registers should be under windows where cold air wants to fall. A grillwork under or near the furnace, but connected, will complete this circuit. |
rboucher | Posted - 8 July 1999 18:34 I do not like the plenum idea especially if this space has a dirt floor and even if it has a proper vapor barrier on the floor. If you have airconditioning, the musty smell that crawl spaces have in the summer will be distributed thru the whole house. Per code ventilation louvers are required although you can shut them but unless you air tight seal them humid outside air will mix in and and eventually raise humidity levels. Even then the humidity will still increase. I speak from experience, I live in large ranch entirely on a crawl built in 1974. I do not have any water problems but still get the musty smell. I have tried louvers open in summer and presently I am trying them closed this summer. The closed position has resulted in lower crawl temperatures but humidity levels have risen lately due to high humidity outside. Also, I am still getting some condensation on the ducts located there. Believe it or not the ducts were not insulated. The issue of insulating ducts when perimeter insulation is installed is a whole other discussion as is open louvers or shut ones. If you search for info. on recommendations on crawl space insulating and ventilating you will find all kinds of conflicting info. Basically after living 10 years plus with a crawl space I have come to the conclusion that they are a big pain in the neck and not just because of the ventilatiom issue but also from a maintenance stand point. Next time I will opt for a properly waterproofed, reinforced, drained, insulated, and backfilled basement. |