Weatherize Your Home

Weatherize Your Home­Caulk and Weather Strip

Warmed or air-conditioned air mixes with outside air through gaps in your home's thermal envelope-exterior walls, win­dows, doors,the roof, and floors. Such air leaks can waste large amounts of energy.  

Most experts agree that caulking and weather stripping any gaps will pay for itself within one year in energy savings. Caulking and weather stripping will also alleviate drafts and help your home feel warmer when it's cold outside. However, these two weatherization techniques can't replace the need for proper insulation throughout your home.

Accessing air quality                 

Because caulk and weatherstripping limit indoor‑outdoor air circulation, you should assess your indoor air quality before you apply them. Some homes contain dust, mold, carbon dioxide, and other indoor air contaminants. Sealing air leaks in these homes, without proper ventilation, can also seal in their indoor air pollutants. There­fore, any plan to tighten the thermal enve­lope of a home should be accompanied by a look at your home's ventilation needs.

This fact sheet does not cover indoor air quality assessment and ventilation. See "Resources" at the end of this fact sheet for whom to contact for more information.

Detecting air leaks

You may already know where some air leakage occurs in your home, such as an under-the-door draft that makes you want to put on socks. But you'll probably need to search to find the less obvious gaps.

• Door and window frames
• Mail shutes
• Electrical and gas service entrances  
• Cable TV and phone lines
• Outdoor water faucets
• Where dryer vents pass through walls
• Bricks, siding, stucco, and foundation
• Air conditioners
• Vents and fans.

Depressurize your home to help detect leaks.  On a cool, very windy day, turn off the furnace.  Shut all windows and doors.  Turn on all fans that blow air outside, such as bathroom fans or stove vents.  Then light an incense stick and pass it around the edges of common leak sites.  Wherever the smoke is sucked out of or blown into the room, there's a draft.  Or just turn on all your exhaust fans (don't need to turn off the furnace) and try one of these methods:

• At night, shine a flashlight over all potential gaps while a partner observes the house from outside. Large cracks will show up as rays of light. Not a good way to detect small cracks.
• Shut a door or window on a piece of paper. If you can pull it out without tearing, you're losing energy.

For a more thorough and accurate measurement of air leakage, you can hire a technician to conduct a blower door test in your home.  Blower doors are variable-speed fans with a frame and shroud that allows them to fit inside a variety of door frames.  Pressure gauges determine airflow through the fan, as well as fan-induced pressure.  The leakier a house, the more airflow required to induce a pressure difference.  When used as a diagnostic tool, a blower door can also reveal the location of many leaks.

You can use a caulking compound to seal leaks in a variety of places throughout your home, including around windows and door frames.  In addition to plugging air leaks, caulking can also prevent water damage inside and outside of the home when applied around faucets, ceiling fixtures, water pipes, drains, bathtubs and other plumbing fixtures.

Caulk forms a flexible seal for cracks, gaps, or joints less than 1 quarter-inch wide.  Most caulking compounds come in disposable cartridges that fit in half-barrel caulking guns (if possible, purchase one with an automatic release.  Some pressurized cartridges do not require caulking guns.  When deciding how much caulking to purchase, consider that you'll probably need a half-cartridge per window or door and four cartridges for the foundation sill.

Caulking compounds can also be found in aerosol cans, squeeze tubes, and ropes for small jobs or special applications.  Water-based caulk can be cleaned with water, while solvent-based compounds require a solvent for cleanup.  Caulking compounds also vary in strength, properties, and prices.  See Table 1 on page 4 for a description and comparison of the common caulking compounds.

Application

• Although not a high-tech operation, caulking can be tricky.  Read and follow the instructions on the compound cartridge.  And save yourself some trouble by remembering a few important tips:
• Clean all areas to be caulked for god adhesion.  Remove any old caulk and paint, using a putty knife or a large screwdriver.  Make sure the area is dry so you won't seal in moisture.
• Hold the gun at a consistent angle.  Forty-five degrees is best for getting deep into the crack.  You know you've got the right angle when the caulk is immediately forced into the crack as it comes out of the tube.
• Caulk in one straight continuous stream, if possible.  Avoid stops and starts. Send caulk to the bottom of an opening to avoid bubbles. 
• Make sure the caulk sticks to both sides of a crack or seam. 
• Release the trigger before pulling the gun away to avoid applying too much caulking compound. A caulking gun with an automatic release makes this so much easier. If caulk oozes out of a crack, use a putty knife to push it back in. 
• Don't skimp. If the caulk shrinks, reapply it to form a smooth bead that will seal the crack completely.

Table 1. Common Caulking Compounds

Weather Stripping

Selection

Weatherstripping can seal leaks around movable joints, such as windows or doors. You need to choose a type of weatherstriping that will withstand the friction, weather, temperature changes, and wear and tear associated with its location. For example, when applied to a door bottom or threshold, weatherstripping could drag on carpet or erode as a result of foot traffic. Weatherstripping in a window sash must accommodate the sliding of panes up and down, sideways or out. The weatherstripping you choose should seal well when the door or window is closed while allowing it to open freely. 

Choose a product for each specific location. Felt and open-cell foams tend to be inexpensive, susceptible to weather, visible, and inefficient at blocking airflow. However, the ease of applying these materials may make them valuable in low-traffic areas. Vinyl, slightly more expensive, holds up well and resists moisture. Metals (bronze, copper, stainless steel, and aluminum) last for years and are affordable. They can also provide a nice touch to older homes where vinyl might seem out of place. You can use more than one type of weatherstripping to seal an irregularly shaped space. Take durability into account when comparing costs. Table 2 on page 6 describes and compares commonly used weatherstripping. To determine how much weatherstripping you will need, add the perimeters of all windows and doors to be weather stripped. Then add 5 to 10 percent to accommodate any waste. Also take into consideration that weatherstripping comes in varying depths and widths. 

Application

Weather-stripping supplies and techniques range from simple to the technical.  Consult the instructions on the weather‑' stripping package. Here are a few basic guidelines: 

• Weatherstripping should be applied to clean, dry surfaces in temperatures above 20° F (-7° C). 
• Measure the area to be weather stripped twice before you cut anything. 
• Apply weatherstripping snugly against both surfaces. The material should compress when the window or door is shut.

Table 2. Common Weatherstripping

A comprehensive online resource for DOE's energy efficiency

Resources

The following are sources of additional information on caulking, weather  the mention of any resource constitute a recommendation or endorsement.

Ask an Energy Expert

DOE Energy Efficiency and Renewable Energy
Clearinghouse (EREC)
P.O. Box 3048
Merrifield, VA  22116
Phone:  1-800-DOE-EREC (1-800-363-3732)
TDD:  1-800-273-2957
Fax:  (703) 893-0400
e-mail:  doe.erec@nciinc.com
Online submittal form:
www.eren.doe.gov/menus/energyex.html

Consumer energy Information Web site: www.eren.doe.gov/consumerinfo/

Energy experts and information specialists at EREC provide free general and technical information to the public on many topics and technologies pertaining to energy efficiency and renewable energy, including air quality assessment, which is not covered in this fact sheet.

DOE Office of Building Technology, State and Community Programs (BTS)
Web site:  www.eere.energy.gov/buildings/

In partnership with industry and government, develops, promotes, and integrates energy technologies and practices to make buildings more efficient and affordable.

Indoor Air Quality Information Clearinghouse (IAQINFO)
Environmental Protection Agency
P.O. Box 37133
Washington, DC  20013-7133
Phone:  1-800-438-4318, (703) 356-4020
Fax:  (703) 356-5386
E-mail:  iaqinfo@aol.com
Web site:  www.epa.gov/iaq/

Helps provide information and answer questions about indoor air pollution.

Weatherization Assistance Program

BTS
Web site:  www.eere.energy.gov/weatherization/

Works with local and state weatherization programs throughout the United States, reducing heating and cooling costs for low-income families and individuals.

Web Sites

Caulking and Weatherstripping
Energy Efficiency Resource Gateway
Louisiana Department of Natural Resources
Web site:  www.leeric.lsu.edu/energy/caulking/

An online brochure on the hot-to-and what-to-use for caulking and weather stripping.

Home Tightening-Home Series
Iowa Energy Center

Shows how stopping air leaks in your home with caulk and weatherstripping is the most effective way to save energy in your home and increase a home's comfort.

Remodeling How-To's:  The Ways of Weather Stripping 
Remodeling Online
Web site:  http://www.remodeling.hw.net/

Features article on "The Ways of Weather Stripping" best suited to older homes.

Residential Energy Efficiency Database (REED)
Web site:  www.its-canada.com/reed/

An information source for individuals seeking understanding on techniques, technologies, and products related to residential energy efficiency.

A comprehensive online resource online resource for DOE's energy efficiency and renewable energy information.

Organizations
Alliance to Save Energy
1200 18th Street NW, Suite 900
Washington, DC  20036
Phone. (202) 857-0666
Fax:  (202) 331-9588
E-mail:  info@ase.org
Web site:  www.ase.org

A nonprofit coalition of prominent business, government, environmental, and consumer leaders who promote the efficient and clean use of energy worldwide.

Weatherization Guide
Urban Options
Web site:  www.urbanoptions.org/resources/guides/weatherizationGuide.php

Takes you step by step through all the basics of plugging air leaks and adding insulation in your home.

Energy Saving How To's
Do It Yourself.com
Web Site:  www.doityourself.com/energy/

Covers the basics of most weatherization topics.

Weatherizing Your Home
The Resource:  Consumer Education
Nebraska Extension Publications
web site:  www.ianr.unl.edu/pubs/consumered/

Click on "Energy  Conservation" to reference information on weatherizing your home, using both caulk and weatherstripping.

Further Reading

Air sealing, BTS, November 1999.  Available in PDF at www.eere.energy.gov/buildings/info/documents/pdfs/26448.pdf in print from EREC (see "Ask an Energy Expert" above).

Consumer Guide to Home Energy Savings, American Council for and Energy-Efficient Economy (ACE³), Washing, D.C. Available from ACE³ at www.aceee.org or by calling (202) 429-0063.

Energy Savers:  Tips on Saving Energy & Money at Home, DOE.  Available online in HTML and PDF at www.eere.energy.gov/consumerinfo/energy_savers/, and in print from EREC (see "Ask an Energy Expert).  Spanish version also available.

Insulation Fact Sheet, DOE. Available online in HTML at www.ornl.gov/roofs+walls/insulation/ins_01.html and in print from EREC (see "Ask and Energy Expert").

Residential Energy:  Cost Savings and Comfort for Existing Buildings, J. Krigger, Saturn Resource Management, Helena, MT, 2000.  Phone:  1-800-735-0577; Fax:  (406) 442-1316; Web Site:  www.residential-energy.com.

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