Air sealing with caulk, weather-stripping, and other appropriate materials is a fundamental step in making your home more energy efficient. Individual gaps may appear minor, but collectively they can have the same effect as leaving a window open all year long. According to the Department of Energy, proper air sealing of gaps and holes in the attic, crawlspace, and other breaks in the thermal boundary can save 10 percent or more on your energy bills.
Why is air sealing important?
Air sealing the envelope or shell of your home, including
the exterior walls, ceiling, windows, doors, and floors, is often one of the most cost effective ways to improve your home’s energy efficiency and comfort. Air sealing should always be performed before any insulation is added. It can save 10 percent or more on your total annual energy bills.
What does the air sealing improve?
• Reduces utility bills
• Improves comfort, especially during winter and summer
• Reduces noise from the outside
• Prevents allergens, dust, contaminants, and insects from
entering your home
• Improves indoor air quality
• Improves humidity control
• Protects the environment
What areas should be air sealed?
Many air leaks and drafts are easy to find because they are
easy to feel, such as those around windows and doors. Holes hidden in attics, basements, and crawlspaces, however, are usually bigger problems. For example, penetrations in ceilings and floors for electrical wires, plumbing, ducts, chimneys, flue pipes, and recessed lights can be major sources of air leakage. Proper air sealing materials (e.g., caulk, expanding foam, rigid foam board,
weather-stripping, etc.) will vary depending on the nature of the leak and the surface to be sealed.
In two story homes there can be attic areas to which underneath the floors are open. This air penetration between the upstairs floors and the attic areas can also have a negative impact on your electric bill. To seal under the floors expanding foam and rigid foam board are placed between the joists in the attic closing penetrations, before adding insulation if necessary.
Old windows usually can be made more energy efficient, at a
significantly lower cost than replacement windows by using proper air sealing methods. Jambs and trim must be adequately air sealed to optimize energy efficiency potential of both new and old windows. If new windows are installed, they should also contain energy-efficiency features such as low-e coatings and gas filling