It is easy for everyone to overlook the crawl space of a home when thinking green.
When you think of going green you naturally think of light bulbs, appliances, insulation, windows etc. Very few people immediately realize that one of the major sources for energy loss is the crawl space of the home. The foundation vents that were originally designed to allow humidity to escape not only allow hot, humid air to enter in the summer months but also allow cold air to enter in the Winter months. This process makes the heating and cooling system work much harder to compensate for the adverse weather conditions.
Homeowners strive to have their builder use the best windows, insulation, house wrap and other materials to create the tightest most energy efficient home they can. Most people do not consider that having foundation vents allow outside humid or cold air to enter the home. This can be detrimental to the goal of an efficient green home.
Ongoing studies like the one conducted by Advance Energy have proven the theory that an unvented, closed crawlspace is the most energy efficient design in the crawl space of a home. As an added benefit this method also controls humidity in the crawl space and helps to prevent the growth of mold and fungus. When builders design a home with an unvented crawl space they often have to downsize the heating and cooling unit because the home is now not fighting outside elements.
Studies like this have helped to rewrite the building codes throughout the country. The International Building Codes now allow for unvented crawl spaces and most building codes now allow for unvented crawlspaces.
Most building commissioners encourage the practice of unvented crawlspaces in all new construction.
Unfortunately foundation vents have been a standard practice for most crawlspace homes since they started building homes on crawl spaces.
It is common knowledge that if you have a basement you would never leave your windows open year around. Why do homeowners accept the practice of having foundation vents in their crawlspace? A crawl space is nothing but a short basement.