November 1999
Air InfiltrationSummary
Air infiltration can account for 30 percent or more of a home’s heating and cooling costs and contribute to problems with moisture noise, dust, and the entry of pollutants, insects, and rodents. Reducing infiltration can significantly cut annual heating and cooling costs, improve building durability, and create a healthier indoor environment. The size of heating and cooling equipment can also be decreased, which saves additional dollars.
Air Sealing to Reduce Infiltration
Ventilation is fresh air that enters a house in a controlled manner to exhaust excess moisture and reduce odors and stuffiness. Air leakage, or infiltration, is outside air that enters a house uncontrollably through cracks and openings. It is unwise to rely on air leakage for ventilation. During cold or windy weather, too much air may enter the house and, during warm or calm weather, too little. Also, a leaky house that allows moldy, dusty crawlspace or attic air to enter is not healthy. The recommended strategy in both new and old homes is to reduce air leakage as much as possible and to provide controlled ventilation as needed. For simple house designs, effective spot ventilation, such as kitchen and bath fans that exhaust to the outside, may be adequate. For more complex houses or ones in colder climates, whole house ventilation systems may be appropriate. Such systems may incorporate heat recovery, moisture control, or air filtering.
This fact sheet, helpful to practitioners as well as consumers, provides a brief, easy to read summary of how to attack air infiltration in homes. Topics include:
- What are the priorities for air leakage sealing?
- Where are these leakage sites?
- Air leakage sealing materials.
- Air sealing checklist.
Written and prepared for the U.S. Department of Energy by, Oak Ridge National Laboratory:
Southface Energy Institute
404-872-3549
www.southface.org
Oak Ridge National Laboratory
Buildings Technology Center
423-574-5178
4 pages