Sealing Air Leaks: A Point-Blank Way to Improve Your Home’s HVAC Efficiency

Published on: March 12, 2014

It’s bound to happen – as your home ages, holes, cracks and gaps will start to appear in its outer shell. Through these openings, your conditioned air is allowed to escape outdoors while the weather is allowed access inside. Although air leaks are a common problem for many homeowners, they can cost you significant amounts of money in energy losses. Your HVAC system also has to work harder in an attempt to make your home feel comfortable, which can lead to unnecessary repair jobs and reduce system life expectancy. Such energy waste puts avoidable strain on the environment as well. The good news is that sealing air leaks with caulking and weatherstripping is a fairly easy and inexpensive thing to do and can result in a 10 to 15 percent reduction in your monthly utility bills. Learn more about these air sealing techniques and get tips to make the application process go smoothly.

Before You Start Sealing Air Leaks

Before you run off to the local home improvement store, it’s important to find the leaks in your home so you have a better idea of the supplies you’ll need. Wait for a day when it’s windy outside to detect air leaks. Walk around the inside of your home’s outer envelope with a lighted smoke pen or incense stick, holding it up next to windows, doors, electrical outlets, plumbing fixtures and any other areas where air may have the chance to escape. When the smoke wavers, you’ve discovered an air leak. Write down the locations where you’ve spotted leaks.

It’s also important to make sure air sealing won’t compromise your indoor air quality. Determine your ventilation needs before starting the process. Lastly, all areas that you’re going to treat should be cleaned and thoroughly dried before sealing air leaks.

Caulking Basics

Gaps, cracks or joints that are less than 1/4-inch wide between building components and materials should be sealed with caulking. Most likely, you will apply the caulk using a disposable half-barrel caulking gun that contains a cartridge of caulk, but pressurized cartridges that don’t require a caulking gun are available as well. Several different types of materials used for the caulking compound are available in various quality levels and price ranges.

Caulking Application Tips

  • Carefully follow the instructions on the caulking package.
  • Apply caulk only when it’s dry outside and the temperature is above 45 degrees.
  • Get rid of any old caulking or paint and then clean and thoroughly dry the area before applying new caulk.
  • Apply the caulk in a single continuous stream.
  • Let go of the gun’s trigger before pulling away so you don’t apply too much.
  • Make sure the caulking adheres well to each side of the seam or crack.
  • Consistently hold the gun at a 45-degree angle when applying caulk into a deep crack.
  • Ensure caulk is applied inside all of the joints and the joint between the wall and frame when applying around windows.
  • Push back caulking that oozes through holes or gaps with a putty knife.
  • For bigger gaps, use expanding spray foam.

Weatherstripping Basics

Air leaks around the moveable features of your home (ie doors and operable windows) are typically sealed with weatherstripping. The type of weatherstripping you’ll use depends on where you intend to install it, as there are several types with different purposes. For example, tension seal (V strip) can be used along the sides of sliding or double-hung windows. The various types come in different depths, lengths and widths, and a variety of materials are available.

Weatherstripping Application Tips

  • Follow package instructions for useful tips. The packaging also indicates the supplies you’ll need.
  • Measure around doors and windows that need weatherstripping and then add 5 to 10 percent to that figure (just to be safe) to determine how much you’ll need.
  • Don’t cut off a section of weatherstripping until you’ve twice measured the area where it’s being applied.
  • Make sure weatherstripping is in one continuous piece along areas where it’s being installed and that it has a snug fit.
  • Generally, use a cheaper type of weatherstripping in locations that don’t get a lot of traffic. Though it’s not as durable, the less expensive weatherstripping is usually effective enough in such areas.
  • Make sure the weatherstripping is thick enough that it creates a tight seal when the door or window is shut without hindering your ability to close it.

Do you need more helpful tips on sealing air leaks? Please contact us to find a contractor in your part of the Southeast United States.