Air leaks waste energy, making homes uncomfortable and expensive to heat. Air sealing corrects the problem and enables comfortable indoor temperature year round.
Using simple tools like dollar bills and a flashlight, home owners can find many leaks that are quick and inexpensive to fix. The energy savings from the work usually pay for itself within a few years.
Caulking
Caulking is the most common method of sealing air leaks around doors, windows and other stationary components in a home. This flexible material can be used indoors and out to seal gaps, cracks and seams less than a quarter-inch wide. Caulking is an effective method for lowering energy costs and is often less expensive than replacing or repairing damaged window frames, door jambs and sills.
There are many different types of caulk available on the market, including silicone, acrylic, butyl rubber and polyurethane. Each type offers its own advantages, but it’s important to use a high-quality caulk with a good seal.
A caulking gun is also essential for this project. A premium caulking gun is designed to be easy to use and will help you achieve a professional-looking result. It’s recommended that you practice using the caulking gun on a piece of scrap wood before starting on your actual window or door frame.
You can purchase a caulking gun at most hardware stores or online. In addition to a caulking gun, it’s a good idea to invest in a set of sealant finishing tools. These are inexpensive, simple to use and offer a consistent finish. They also remove most excess caulk without damaging the surface underneath. Before you start caulking, it’s a good idea to test the area for air leaks by holding a lit candle near suspected gaps on a windy day. If the candle moves, there is air escaping and you should focus your caulking efforts on those areas.
Weatherstripping
As its name implies, weather stripping is a method of sealing gaps around doors and windows. Like caulking, it reduces air leaks and helps to control energy costs. It can also improve indoor comfort and increase resale value.
The first step to applying weather stripping is identifying areas where air leaks are occurring. Stand near the door or window frame and feel for any air blowing. Or, hold a candle up to the frame and see if it flickers, indicating an area that needs sealant.
Once the area has been identified, clean the surface with soap and water to remove any debris or dust. Then measure the gap between the door or window and the frame, adding 5 to 10% for waste (this is standard for most do-it-yourself materials). If you plan on installing a vinyl V strip, foam tape or other material that requires cutting, prepare your tools by using tin snips, scissors or a hacksaw based on the material type.
Vinyl V strips are easy to install on the top or bottom of window sashes, where they fold in and seal when the window is closed. Foam tape is similar, but easier to cut and has an adhesive backing that makes it simple to apply. Felts are another option, and can be used in similar ways, but may not be suitable for high moisture areas.
Sealing Around Doors & Windows
Many older homes have doors and windows with outdated caulking or foam, which lets air in during warm summers and cold winters. Sealing around your windows and doors is an easy DIY project that can save you a lot in heating and cooling costs. Similarly, the same techniques can be used to seal around utilities entering your home, chimneys, dryer vents and pipes, and areas where decks and porches attach to your house.
Before you start sealing gaps and cracks, it’s a good idea to identify where the leaks are coming from. This will help you prioritize your energy-saving projects. If your home’s attic is leaking, for example, it may make more sense to invest in better insulation than addressing the gaps around old windows, which are often not as costly to fix.
The best way to find air leaks is by having an energy audit, including a blower door test, done on your home. But if you’re not ready to invest in an audit, there are still some simple ways to test for air leaks around windows and doors. One of the most popular methods involves placing a candle next to a window or door. If the candle flickers, that indicates a draft from an air leak. Other methods include closing all the doors and windows in your home, and then running a fan. If the fan is unable to keep the room at a comfortable temperature, you have air leaks that need to be sealed.
Sealing Around Vents
Vents and returns, plumbing fixtures and recessed “can” lights are common places where air leaks into the house. Before sealing around these openings, clean the surfaces to remove dust and dirt. Then use expanding foam insulation to seal the gaps (Photos 8 and 9). When using this fireblocking type, read the directions carefully. It may require several coats and should be allowed to dry completely between applications. If possible, insert a piece of fiberglass batt insulation as a backer for a more durable seal.
A drafty home can waste energy and money, and it invites harmful pollutants directly into the living space. These unwanted guests can cause allergies and asthma to flare up, too.
A professional can perform a blower door test to locate the most significant leaks. But if you want to save money, you can identify many of these leaks yourself with a simple tool—a lit incense stick or a thin sheet of paper held up against the surface of the wall or ceiling. When the smoke or paper moves erratically, there’s a gap where air is moving freely. Start with the attic to prevent cold air from seeping down into the basement and warm air from escaping through the top of the house. And don’t forget to seal the attic hatch and the areas around recessed lighting boxes.