Man caulks his windows to air seal and insulate his home
This person is using caulk to seal the gap between their home and the window.

In Texas, our air conditioners use lots of power. In fact, it’s the number one energy-consuming appliance in homes — not just in Texas — but across the United States! That’s why it’s so important that your home is as tightly sealed as possible. If you wonder why your electricity bill’s so high or why your air conditioning is always running, then it’s time you should check to see if you have any air leaks in your home. 

With this article, we’ll show you how to find air leaks, seal them properly, and prevent any drafts from happening in the future. Learning how to air seal your house helps reduce unwanted moisture from coming into the house and improves your home’s air quality. This will save you lots of money on your energy bill and make your home more energy-efficient. 

What’s an Air Leak?

This question might seem obvious, but an air leak is any spot in your house that lets air in or out that shouldn’t. For example, your windows are meant to be opened so they provide natural ventilation for your home. However, they’re not meant to let the hot air in and cold air out during the summer or let the cold air in and warm air out during the winter when they’re closed. That’s when it becomes air leakage instead of natural ventilation. 

Air leaks are also pretty elusive. They can occur anywhere there’s an opening, such as around recessed lighting or small cracks in the brick exterior. Compared to water leaks, air leaks are also more difficult to find and almost impossible to see. But air leaks are easier to spot than you think, and there are several ways you can do it without additional costs. 

How to Find Air Leaks in Your Home

Detecting an air leak in your home is a type of energy audit, an inspection of your home’s energy efficiency. There are two kinds of energy audits: 

  • Do-it-yourself energy audit
  • A professional home audit

A professional energy auditor will inspect your home with tools such as a thermal imaging camera and door blower. These devices can detect the smallest of air leaks that are invisible to the naked eye. But they also cost money, which is the opposite of what you’re trying to accomplish by sealing these drafts. 

With a DIY energy audit, you might not get as thorough of an inspection, but it’s still a great way to spot big drafts, poorly insulated hot water heaters, and old weatherstripping in your home. After this at-home energy audit, you’ll have a much better idea of the steps you should take in your home if you really want to lower your electricity bill.

Start with a Visual Inspection

First and foremost, look around! Pay close attention to the junction points of two materials, such as where your front door meets the wall. If you can see any light coming through, the weatherstripping needs replacing. Other common areas where air may be leaking out or in include: 

  • Wiring holes
  • Windows
  • Sliding doors
  • Where the chimney meets the ceiling
  • Plumbing holes
  • Electrical outlets
  • Openings in exterior walls
  • Cracks where the foundation meets the exterior siding

Other ways to detect an air leak

While you can’t see an air leak, you can feel it. Here are several methods to help you determine whether those common areas above are truly leaking or not.

  • Light a candle, and hold it in front of the common leak sites we listed earlier. Hold the candlestick really still, and if the flame moves, then you have an air leak. It’s an indication that air is either escaping or entering your home through that spot. 
  • Wet your hands with water and hold them next to a potential leak site. If your hand feels cool — as if you were  applying hand sanitizer — it means there’s an air leak. The moving air is brushing your hand and evaporating the water. 
  • At night, have one person stand inside the house, while the other person stands outside with a flashlight. Have the outside person shine a light on any alleged air leak site, and if the light shines through, even just a little bit, then you have a leak. It means the weatherstripping needs to be replaced, or the crack needs to be caulked. 

Now that you know how to detect most air leaks, let’s talk about fixing them. 

Weatherstripping is used for moving parts in your home like windows.

How to Fix the Air Leaks in Your Home

There are two primary ways to correct any air leaks you might find when doing your DIY home energy audit: caulking and weatherstripping. Both solutions are situation-specific, but it’s also a home improvement project that the average homeowner should be able to accomplish without much outside help.

Caulking is for Cracks

Caulk is an umbrella term to describe the many types of sealants used to close the gap between two materials. There are so many types of caulk, from more familiar latex and silicone caulk to the cool-looking expanding spray foam that’s used for larger cracks. 

To learn the correct type of caulk to use for a given situation, we recommend that you follow the helpful advice in this nifty guide. The important thing to remember is caulk should only be used for immobile parts and materials. We don’t recommend caulking something that moves, like windows and doors. Instead, you should use weatherstripping.

Weatherstripping is for Windows and Doors

While stuffing the newspaper in between window frames can help stop them from leaking air, weatherstripping is much more effective and nearly as low-cost. Unlike newsprint, these materials are specifically made to seal air leaks around your home , making it one of the more affordable and easier ways for you to save money.

Again, we defer to home improvement experts to help you determine the right weatherstripping for your windows and doors. In general, replacing the rubber sealants around your door or the felt in your window sashes can save you 10%–20% on your home heating and cooling costs.1

Other Situations That Require Air Sealing Materials

There are more openings in your home than just your windows and doors. There’s also the attic and the chimney to think about, too! However, those sealants aren’t as common as caulking or weatherstripping, so we decided to discuss them separately as a third category of miscellaneous sealants. 

Attic Box

While weatherstripping can be used to seal your attic, the most effective and energy-efficient options is an attic box. This is an extra piece of insulation covering your attic hatch that you can remove if you ever need to go up there. 

You can build one or buy one premade. They might be a little expensive, but since your attic can actually be one of the biggest openings for air leaks in your home, we believe  it’s better to be sealed than sorry. 

Chimney Balloon

Your fireplace is one of the few openings in your home you can’t really use weatherstripping or caulk to correct an air seal. Hence, most homeowners use an inflatable chimney balloon to cover their fireplace opening. It’s a plastic balloon that inflates to seal the opening of your fireplace during the summer when it isn’t in use.

In the winter, you can either deflate the balloon or, if you forget it’s in there, it will automatically deflate the first time the fireplace is used because it’s often heat-sensitive. 

Next Steps to Properly Air Seal Your Home

If you’re an energy-saving fanatic like we are (or if you just want someone else to do all of this for you), then definitely go forward with a full-on professional audit. Besides, getting on your hands and knees to shine a light through cracks in your window isn’t necessarily what we’d call “fun.” 

If you’re still not seeing the energy savings you want after an audit and air sealing, then there’s likely another cause for your high energy usage. For more information on saving money on electricity in your home, visit our energy saving page, where we’ve gathered all of our tips, free of charge for everyone to use!