Article #1397 - Advantages of Conditioned Crawlspaces
Traditional crawlspace designs include passive foundation-wall vents that are supposed to let moisture and contaminants escape outside. Yet field research shows that wall vents may make moisture problems worse. Replacing crawlspace vents with an exhaust fan and drawing house air in to condition the crawlspace reduces moisture problems and can increase energy efficiency.
The International Residential Code (IRC) specifically allows crawlspace designs with an exhaust ventilation system instead of fixed ventilation openings through the foundation walls. To comply, a mechanically vented crawlspace design must have a continuously sealed, vapor-retarding ground cover, have no fixed ventilation openings to the outdoors, and be supplied with a continuously operating exhaust fan.
Additional Information
- Details for Mechanically Vented Crawlspaces - Code Notes
- Does the Energy Code Allow an Unvented Crawlspace?
- What is the Building Envelope?