South Carolina Crawlspace Encapsulation and Energy Efficiency
A building scientist was quoted that venting a crawl space in the southeast US was “lunacy.” This web site is full of information about crawl space moisture control, dew points, relative humidity, mold on floor joists, condensation on air ducts, and cupped hardwood flooring. Most folks agree that all of those issues in a crawlspace can be addressed effectively with a crawlspace encapsulation. But little has been written here or elsewhere about crawlspace encapsulation and energy efficiency.
The parent company of YourCrawlSpace is Carolina Green Energy Systems (www.carolinsges.com). It is the largest comprehensive home energy performance contractor serving South Carolina. We are a participating incentive contractor with all of the major energy utility companies serving the state. As a performance contractor, Carolina Green Energy Systems maximizes the efficiency of a home in the most cost effective ways possible, from the initial energy audit to becoming an energy partner with our customers and monitoring energy savings on an on-going basis in real time.
Carolina Green Energy Systems has made a study of crawlspace encapsulation and resulting energy use. We have participated in research study test homes with the ZEBRAlliance at Oak Ridge National Laboratories. Oak Ridge is a laboratory in Tennessee operated by the US Department of Energy. The fact is, crawlspace encapsulation IS an energy issue.
It is only common sense. From an energy efficiency standpoint, why would anyone want to vent a crawlspace? A crawlspace that has not been encapsulated will be protected from the elements in the winter and therefore naturally be a bit warmer than the outside ambient temperature. Allowing the colder outside air into the crawlspace through crawlspace vents will tend to make the crawlspace colder and increase heat loss, putting more of a load on the heating system.
Just the opposite is true in the summer. Being protected from the elements and probably at least a little below ground, your crawl space will be a cooler than the outside temperature. Warm outside air will enter through the crawlspace vents, increasing the temperature and increasing the cooling load on the air conditioner or heat pump.
Since heating and cooling ducts are usually installed in the crawlspace, venting a crawlspace will increase energy loss from the ducts in both summer and winter. And in the summer, condensation in duct insulation can more than double energy loss from ducts. Nothing will destroy the effectiveness of insulation like moisture. So, the summertime condensation will also decrease wintertime efficiency.
A crawl space encapsulation will not only protect your investment and make your home a healthier and more comfortable place to live, it will also make your home a more energy efficient (and less expense) place to live.