Basic Concepts

• Identify where air leakage occurs in the home

• Types of materials used to stop air leakage

Two conditions needed for air leakage:

– A hole– Driving force

across the hole

AIR

Lots Of Driving Forces

Image courtesy of Southface Institute

humidityhumidity

rainrain

windwind

humidityhumidity

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Driving forces move air in predictable directions

MoreMorePressurePressureMoistureMoisture

HotHot

LessLessPressurePressureMoistureMoisture

HotHot

You can’t do anything about driving forces,

so seal the holes!

AIR

Air seeks the path of least resistance.

Air will choose the largest

available path.

Where is air leakage greatest in the home?

• Ducts• Fireplaces• Plumbing

penetrations• Doors

• Windows• Fans and vents• Electrical outlets• Floors, walls and

ceilings

Air Leakage

Big HolesChases

Plumbing penetrations

Droppedceilings

Access panelsCeiling fixtures

Ducts

Sill plates

Vents

Window openings

Door openings

Air Leakage Results In:

• Wasted energy• Stack effect• Drafts• Discomfort

Floors and Ceilings

Stopping the Leaks!

• Start at the top• Seal and insulate duct work • Seal low spots• Provide combustion air for

combustion appliances• Use caulk, foam or

weatherstripping

Caulk

Foam

Weatherstripping

Weatherstripping Doors

Outlets and

Switches

What Caulking to Use?

What Kind of Weatherstripping?

Chimneys

Storm Windows

Key Points:

• Air leakage results = energy loss and discomfort

• Seal air leaks at top first, then lower and be mindful of combustion equipment

• Cauling, foam and weatherstipping can be used to seal air leaks

For More Information

• Major Resources:– http://www.eere.energy.gov/

buildings/building_america/

– http://www.energystar.gov/homes