Sustainable Living: Seal Air Leaks to Save Energy This Winter

Windows in home office
Photograph provided by MGE

As the days get shorter and temperatures get cooler, it’s an ideal time to prepare your home for winter. Sealing air leaks should be at the top of your to-do list. This is an effective way to increase comfort and, according to the U.S. Department of Energy, could save up to 20 percent on energy costs.

Air sealing may sound like a daunting task, but some of it can be a DIY project. There are simple steps you can take to help keep your heated air inside this winter.

Weatherstripping for Doors
Weatherstripping works well to seal air leaks around movable components, like doors. It is available in many different materials, so it’s important to choose the right type for your project.

• Door bottom: Weatherstripping applied to a door bottom can drag on carpet. It should be able to withstand wear and tear and friction, as well as temperature changes. Door-sweep weatherstripping is a good option. The mount is made of aluminum or stainless and the “sweep” is a brush made of plastic, vinyl, sponge, or felt. Door-sweep weatherstripping is easy to install and adjusts for an uneven threshold.

• Sides and top of your door: Choose a product made of felt, foam, tape, rubber, or vinyl.

Proper application is key. Be sure your weatherstripping meets tightly in the corners. Apply one continuous strip along each side and then seal the entire door jamb.

Don’t forget your attic door or hatch. For pull-down attic stairs or an attic door, apply weatherstripping to the edges and add at least four one-inch pieces of foam board insulation on the back of the door or hatch. Another option is to apply an insulated attic stair cover. If you have a hatch, seal the opening with self-sticking weatherstripping.

Caulk for Drafty Windows
Caulk is a flexible material that can be used to seal air leaks around windows. Caulking compounds come in a variety of strengths and prices. Most are available in disposable cartridges that fit in a caulking gun. Additionally, some caulk comes in squeeze tubes, ropes, or aerosol cans.

Good options for windows include:
• Water-based foam
• Expandable spray foam, which works well for large or irregular gaps
• Rubber, which can last 10 years or more
• Temporary caulk, which can be applied to the inside of windows and peeled off when the weather warms up in spring

Caulk should be applied during dry weather when the temperature is at least 45 degrees Fahrenheit. Apply caulk in one continuous stream. Be sure to seal cracks completely and allow sufficient time for the caulk to dry. It often takes 24 hours for it to fully cure depending on weather.

Window film is another inexpensive way to help reduce drafts and condensation in winter. It’s easy to apply and can even be used over mini blinds. If you have an older home, remember to change your screens to storm windows.

More Air Sealing
Don’t put away the caulk when you’re done sealing your windows. There are several other places around your home where it can be useful.

• Fireplace: Over time, the space between your mantle and drywall can crack and become leaky. Additionally, if you have a woodburning fireplace, check the damper. If it doesn’t close properly, it can be a major source of heat loss.

• Recessed lighting (in a ranch home or on the second floor of a two-story home): If fixtures are not airtight, warm air can escape into the attic. Not only will you lose heat, but it will warm your attic and snow on the roof, which can cause ice dams. These ridges of ice that form at the edge of a roof prevent melting snow from draining.

Even if a can light is airtight, you should caulk between the can light housing and drywall. Can lights also require a fire barrier. Such material is used to keep the insulation in the attic away from the fixture housing, which can get hot even if you have LED lights. It’s important to know which type of can light you have—some are rated for insulation contact and others are not. Consult a professional air sealer to ensure safety and effectiveness when sealing can lights.

• Exhaust fans in the bathroom and kitchen: Remove the plastic cover and add caulk between the fan housing and drywall to seal leaks.

• Places where plumbing, ducting, or electrical wire comes through ceilings, walls, floors, or soffits.

Need a Little Help?
If you don’t have the time or desire to take on air sealing or other energy-efficiency projects, an energy audit may be a solution. FOCUS ON ENERGY® can help. As Wisconsin utilities’ statewide energy-efficiency and renewable-resource program, Focus on Energy works with residents and businesses on cost-saving, energy-efficiency, and renewable-energy projects.

Consider taking a comprehensive, whole-home approach when looking to boost comfort and energy efficiency. Focus on Energy offers financial incentives to homeowners for making qualified energy-saving improvements. Learn more at .

Ask the Experts
MGE is available to answer your questions and provide tips on saving energy for the upcoming winter and throughout the year.

MGE Home Energy Line: MGE’s energy experts are available between 8:00 a.m. and 4:30 p.m. Monday through Friday. Call 608.252.7117 or email .

Other resources for saving energy include: