LEARN MORE AT
energystar.gov
ENERGY STAR®, a U.S. Environmental Protection Agency
program, helps us all save money and protect our environment
through energy efficient products and practices. For more
information, visit www.energystar.gov.
Air Sealing
Improves Energy Efficiency and Air Quality
In typical homes, air leaks are often found at cracks, small holes, and penetrations for
plumbing, wiring, lighting, and ductwork. Together, these leaks can add up to as
much air loss as having an open window! It's easy to imagine how this can increase a
homeowner's utility bills and reduce comfort.
Sealing a home's envelope —its exterior walls, ceiling, and floors—is an important step
in controlling the indoor environment and lowering energy bills. The goal is to reduce air
leakage as much as possible, while providing ventilation as needed for fresh air. In
other words, "build it tight and ventilate it right."
BENEFITS OF AIR SEALING
•	Improved Comfort. Drafts felt during
the winter are often the result of
unsealed cracks and holes. Sealing
homes tightly typically results in
fewer drafts and less noise.
•	Lower Utility Bills. Air leakage and
improperly installed insulation can
waste 20 percent or more of the
energy used to heat or cool a home.
With effective air sealing and
insulation, heating and cooling
systems will not need to work as
hard.
- Air leaking out of the he
• Improved Indoor Air Quality. A tighter
home envelope reduces the amount of
humidity, dust, pollen, and pests that
can enter the home and helps improve
indoor air quality.
Common air lealis in a standard home
• Increased Durability. When warm air leaks through a home's floors, walls, and attic, it can
come in contact with cooler surfaces where condensation can occur. Moisture that occurs
in these construction assemblies encourages mold growth, ruins insulation, and even
compromises the structural elements of the home. Reducing air leakage helps minimize
moisture problems and increase the home's durability.

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LOCATION OF COMMON AIR LEAKS
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While poorly sealed windows and doors can
contribute to air leakage, the bigger sources are
typically holes and penetrations through the home's
envelope that are hidden from view. These include
penetrations for piping, wiring, lighting, and duct
work as well as seams where materials join. It is
easiest to seal these areas during construction
because access is much more limited afterwards.
Builders can use a variety of products to seal a
home's envelope, such as caulks, foams, gaskets,
weatherstripping, door sweeps, and house wraps.
For homes that are sealed very tightly, mechanical
...	....	. .	Holes for wiring are sealed with
ventilation systems are available to provide a
expanding foam. These tiny
controlled amount of fresh air.	penetrations can lead to significant
air leaks if left unsealed.
A BETTER FUTURE
ENERGY STAR is a voluntary partnership between the government and more than 9,000
organizations, including more than 3,500 of the nation's home builders. Together with home
buyers and their families, we are working to achieve a common goal —protecting the
environment for future generations by changing to more energy-efficient practices and
products today.
ENERGY STAR is the government-backed symbol for energy efficiency. It identifies new
homes, buildings, and more than 50 types of products that are energy efficient and offer the
features, quality, and performance that today's consumers expect. Products that can earn the
ENERGY STAR include windows, heating and cooling equipment, lighting, and appliances. To
learn more about ENERGY STAR, visit www.energystar.gov.

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