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.
Efficient Duct Systems
Optimize the Home's Comfort Delivery System
To create a comfortable home, an efficient duct system is a must. Ducts—known
collectively as the air distribution system —carry air from the central heater or air
conditioner to each part of the home and back again. In a typical house about
20 percent of the air that moves through the duct system is lost due to leaks, holes,
and poorly connected ducts. That's why the duct systems found in ENERGY STAR
qualified homes are third-party tested for tightness and verified to be properly
insulated.
BENEFITS OF EFFICIENT DUCT SYSTEMS
Improved Comfort. When ducts are properly sealed and insulated, they deliver
conditioned air more effectively to all rooms —helping to ensure a more constant
temperature throughout the home.
Lower Utility Bills. The average
homeowner spends more than $600
on space heating and cooling each
year. Tightly sealed and well
insulated ducts found in ENERGY
STAR qualified homes can reduce
annual utility bills by $120 or more.
Improved Indoor Air Quality.
Leaky ducts in attics, unfinished
basements, crawl spaces, and
garages can allow dirt, dust,
moisture, pollen, pests, and fumes
to enter the home. Sealing these ducts
helps improve indoor air quality.
Conditioned Air
Lost Into Attic
Leaks at Air
Hardier Cabinet
and Access Panel
Supply
Air Duct
Return
/ Air Duct
Ducts Leak at
Joints and
Connections
- Unconditioned
Air Drawn
Into System
Typical Places Where Ducts Leak
• Lower Equipment Costs. When ducts are leaky, the heating and cooling system
has to work harder to condition the home. Duct sealing, along with proper
insulation, allows the installation of a smaller, less costly heating and cooling
system.

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BUILDING EFFICIENT DUCT SYSTEMS
Techniques and practices that provide an efficient and effective duct system include:
Ducts in Conditioned Spaces. Ducts operate
more efficiently in conditioned air at room
temperature. They do not work as well in
excessively hot or cold attics and crawl
spaces.
Sealed Ducts. EPA promotes the use of mastic
and/or Underwriters Laboratory (UL) 181
approved tapes, such as metal-backed tape, to
seal ducts. These materials more effectively
seal leaks around duct joints and seams than
standard "duct tape."
Insulated Ducts. Leaky ducts and poorly sealed
connections can waste 20 percent or more of the air that you pay to heat and cool. To
minimize this energy loss, EPA first recommends installing ducts in conditioned spaces. Where
this is not possible, ducts should be insulated as recommended by the International Energy
Conservation Code (IECC).
Right-Sized Ducts. Ducts in ENERGY STAR qualified homes are sized based on the Air
Conditioning Contractors of America (ACCA) Manual J and Manual D calculations. This helps
to ensure that the ducts accommodate the air flow requirements of the heating and cooling
system for efficient distribution of heated or cooled air.
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.
F'LENUM
MV.vAWA'AWAW.Va "I

-AIR HANDLING
UNIT LOCATED
IN CLOSET
INSULATED
BUILDING
EKVELOPF
RETURN A!R DUCT -
L—STABLE AIR
TEMPERATURES
A Duct System Located in Conditioned Space
SUPPLY AIR
DUCT

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