Sealing Air Leaks: A One-Day Task That Can Have a Positive Ripple EffectPublished on: November 8, 2013
Many homes around the Southeast suffer from a serious problem with a simple solution – air leaks. Leaks around walls, doors, plumbing entrances and elsewhere let indoor air escape while allowing outdoor air, moisture and pollutants in. This happens no matter how much insulation you have, but sealing air leaks can help. Sealing air leaks around your home has benefits that build on one another. You’ll first notice fewer uncomfortable drafts and moisture issues, then you’ll find your heating and air conditioning expenses have fallen. Over the years, you’ll also notice the building materials in your home last longer because they aren’t subjected to dirt and moisture from leaks.
If you’re looking to weatherize your home, taking care of these leaks is one of the first things you should do. In fact, sealing air leaks around walls, floors and ceilings is the number one job on the Department of Energy’s weatherization priority list. To get started with this simple, affordable home improvement job, you’ll need little more than caulk, weatherstripping and a day or two of free time.
Benefits of Sealing Air Leaks: Saving Energy Is Just the Beginning
Although you may think of energy savings as the main benefit of sealing air leaks, there’s a lot more you’ll get out of this basic home improvement job.
- Lower energy bills – Your home may be leaking 20 percent or more of the conditioned air your furnace and A/C produces. With a leaky home, you’re essentially heating and cooling the great outdoors. By sealing the leaks, you can keep more of that expensive warm or cool air inside so you won’t have to spend as much to stay comfortable.
- A more comfortable home – Nothing ruins the comfort of your home like being unable to sit near windows because of the cold drafts. Air sealing your home stops these drafts, keeping your walls, floors and ultimately your whole home more comfortable. A quieter home is another benefit you’ll enjoy. Sealing cracks and gaps helps keep out noise from the street and neighboring homes.
- Healthier indoor air – Along with the outdoor air that leaks in come contaminants like dust, pollen, mold spores and urban air pollution. Your HVAC air filter removes some of these, but the contaminants will still have plenty of time to circulate and aggravate your allergies or asthma. By blocking the air leaks you can enjoy better indoor air quality and possibly better health.
- Better humidity control – With the high humidity levels in the Southeast, the last thing you want is a building issue that invites in moist air. That’s just what air leaks do, though. By stopping the leaks, you’ll have better control over your indoor humidity levels. You’ll feel more comfortable and you may need less heating and air conditioning, too.
- Fewer pest infestations – Where air can enter, so can pests like ants, cockroaches and mice. Sealing air leaks keeps the bugs and rodents outside where they belong.
- Fewer maintenance issues – When cool air leaks into your warm home (or vice versa in summer), it can cause condensation in the walls, floors and other unseen areas. Over time, this moisture buildup degrades insulation, drywall, wood and other building materials. Condensation and humidity from air leaks also encourages the growth of mold, which eats away at building materials. Sealing air leaks protects your home from the costly damage moisture and mold can do.
Finding the Leaks Is the First Step
The most obvious sign of an air leak is a cold draft in winter. Dirt buildup around a window, electrical outlet or utility line entrance is another indication. Anywhere you notice drafts and dirt should be first on your list of places to air seal. To find smaller leaks, you can use an incense stick, smoke pencil or even a piece of tissue. Wait for a windy day and turn off your heating or A/C, any fuel-burning appliances such the gas stove and any ventilation fans. This helps depressurize your home and reduces indoor drafts. Walk around your home and hold the incense stick or tissue up to areas that may be leaking. If air is coming through, you’ll notice the smoke or tissue move sideways.
This quick do-it-yourself inspection goes a long way toward turning up leaks, but it won’t find them all. To make sure you catch all your home’s energy-wasting leaks, call in a heating and cooling professional to perform a blower door test. In this test, the technician uses a large fan to thoroughly depressurize your home so even the tiniest leaks are detectable.
Where to Look for Leaks
If your home is like most, your attic, basement and crawl spaces will be the biggest sources of air leakage. Here you may find large holes that should be sealed as soon as possible.
Places to seal in the attic include the outside edges of the attic hatch, recessed lights, knee walls, dropped soffits and ceilings, and plumbing vent stacks. In the basement, leaks are common around the sill plate, rim joists, HVAC duct penetrations, where the floor and wall meet, and where utilities such as plumbing pipes and electrical lines enter.
Your main living space comes next. Research has shown floors, walls and ceilings account for around 30 percent of the air leakage in the average home. Another 20 percent comes from around windows and doors. The fireplace is another big source of air leakage.
Look for leaks around places such as:
- Window and door frames
- Over and under baseboards
- Around electrical outlets
- Penetrations for gas lines, plumbing and wiring
- Air and heating vents
- Outdoor water faucets
- Penetration of the A/C line or heat pump
- Fireplace dampers
Sealing Air Leaks With Caulk
For sealing air leaks of 1/4-inch or smaller on non-movable building features, caulk is your material of choice. Caulk can be used on window and door frames, around the fireplace and along baseboards among other places.
The type of caulk you need depends on what you’re planning to seal, whether that’s wood, metal, masonry, glass, plastic or another material. That said, for most home air sealing jobs, siliconized latex, acrylic latex, acrylic urethane or elastomeric caulk will work well. No caulk can handle every situation, though, so read the product’s instructions before you buy.
When it comes to application, there a few basic guidelines to follow.
- Choose a quality gun – Look for a caulk gun with moveable plates and a smooth plunger rod. These offer better control than ratcheting plungers with notched plunger rods.
- Clean up first – Before caulking a surface, remove all old caulk, paint and other material. Wipe down the area with soapy water and let it dry thoroughly
- Use backer rods as needed – For leaks of 1/4 to 3/8 of an inch wide, caulk alone may crack and fail to seal. To prevent this, use backer rods, or foam rods that help fill in the space. Choose a size that’s slightly larger than the gap you need to seal so the rod can be compacted firmly into the gap.
- Apply with care– Hold the caulk gun at the angle that best ensures caulk reaches the bottom of the gap and adheres to both sides. This is usually a 45-degree angle. Keep the gun at a consistent angle and apply the caulk at a steady pace. Aim to apply a single continuous line of caulk along each side of the area you’re sealing.
Sealing Air Leaks With Weatherstripping
Weatherstripping is designed to block leaks where two moveable surfaces come together. This includes the inside of your doorstops and the inside tracks of sliding windows and double-hung windows. Applying weatherstripping is even easier than caulking, but you’ll still need to follow some guidelines.
- Choose quality – Skip the cheap foam and felt strips, which deteriorate quickly, and opt for vinyl weatherstripping. The v-strip type typically provides a better seal than the hollow tube type. Metal weatherstripping is another good option for long-term durability.
- Plan ahead– Before you buy your materials, measure the areas to be weatherstripped. To account for mistakes, buy around 10 percent more weatherstripping than you think you’ll need.
- Prepare your surfaces – Only apply weatherstripping to clean, dry surfaces and preferably during warm, dry weather.
- Check your work– To ensure a good air seal, the weatherstripping should compress when you close the door or window. It shouldn’t make the door or window hard to close, though.
While you’re working on improving your home’s energy efficiency, consider contacting a heating and cooling technician for a professional energy audit that includes duct testing and a thermographic scan. The knowledge these tests provide will help you improve your heating and cooling system’s efficiency and your insulation levels.
If you’re in the Southeast and looking for ways to save energy, keep your home more comfortable and boost your indoor air quality, get in touch with us today. We’ll help you find a reliable local contractor so you can start enjoying the benefits of home efficiency upgrades as soon as possible.