Checking for Air Leaks in your AC

Over time, wear and tear can cause leaks in your air conditioner. If you ignore these leaks, it can end up damaging your system or increasing your energy bill. Taking the time to examine your home for air leaks can help you address the problem before it becomes a major issue.

What Are Air Leaks?

Your air conditioner is a finely tuned system that carefully moves air around your house and through your AC unit. When a gap causes air to go to the wrong place, you get an air leak. If a leak is in your duct, it causes air to seep out into your attic instead of exiting your AC vents. You can also have leaks around areas like outlets or light fixtures that cause air to leak into your walls. Many leaks occur around windows and doors where air may leave your home instead of cooling it.

There are several potential issues associated with air leaks. They reduce the efficiency of your air conditioner by sending all your cold air out of your home. Another problem is that really severe air leaks can drop the overall pressure inside your AC system. This can result in airflow problems that cause frozen evaporator coils, blown compressors, and more.

Be on the Lookout for These Signs of Air Leaks

Every home will have at least a few small air leaks, but some houses may have so many leaks that they impact the cooling process. The first sign of a major air leak problem is usually high utility bills. With a lot of your cool air going into walls, attics, and the outdoors, you end up having to pay a lot more to keep your home cool. You may be spending hundreds of extra dollars each year paying for leaked air.

Another potential sign of an air leak is dusty in your home, especially around AC vents. When your leak is in your ductwork, it is easy for dusty attic or basement air to get sucked into your system. This can lead to a thick coating of grime around air vents. One of the most unpleasant signs of an air leak will be uneven cooling. Air leaks keep your home from circulating AC properly, so you might find that spots like your bedroom are randomly freezing cold or burning hot.

Check Your Ducts for Leaks

Since so many leaks happen in the ducts, this is a good place to start checking for holes. Turn on your AC and shine a strong light on your ducts to find any obvious tears. If you notice any spots covered with duct tape, it may be a sign that a past homeowner tried to cover up a tear poorly, leading to more leakage. Many leaks occur around duct joints as well. Hold your hand near each duct joint to see if you feel any air blowing.

Explore Common Leak Sites for Air Leaks

Once you have examined your ducts thoroughly, it is time to check out the rest of your home. Go over sites where air leaks are common to see if you can feel any air leaking through. Sometimes, a leak is strong enough that you can put your hand over the site and feel air rushing past. You can also hold a piece of tissue paper near the site to see if it moves. If you light something that gives off visible smoke, you’ll see the smoke twirl or flow when it encounters a leak.

Just about anywhere in your home where there is a seam or joint may be a site of a leak. Make sure to check all of these common indoor and outdoor leak sites while your AC is running:

• Spots where chimneys meet siding
• Outdoor water faucets
• All corners
• Locations where the foundation meets siding or brick
• Electrical outlets
• Door frames and window frames
• Baseboards
• Attic hatches
• Dryer vent connections
• Any fans and vents
• Dampers on fireplaces
• Entrances for electric, gas, cable, and internet
• Switch plates
• Wall-mounted devices

Use a Fog Machine to Spot Small Leaks

Every home will have imperceptibly tiny leaks that cause some AC to escape. If you want maximum efficiency, try using a fog machine to find these leaks. Start by sealing up all the air vents in your home. Then, run a fog machine near the blower intake for your air conditioner. The fog will make airflow visible, so it is possible to see exactly where all the air is leaking out of your home. Keep in mind that your whole house will fill up with fog if you have a major leak. It might be better to hold off on this test until you have addressed the bigger leaks.

Test Your Home With Pressurization Testing to Find All Leaks

If you want to make sure your home is as leakproof as possible, you may want to try an airtightness test. This is a type of test that can tell you exactly how much air your home is losing due to leaks. During this test, professionals will place large blower fans in an external opening and then pressurize the building. They can then use certain gauges to tell how much air is escaping from leaks in your building. Then, you can use this knowledge to hunt down small air leaks that may have gone unnoticed.

How to Fix Air Leaks

The best method for fixing an air leak will depend on the location of the leak. The simplest leaks to fix are often in ducts, where a mastic or special metallic tape can be applied to the exterior. Leaks around doors and windows may be solved with basic weatherstripping. Use a foam sealant or caulk to line any cracks around doors and windows. If the air leaks are between the actual parts of your window though, things might be trickier. You may end up needing to replace the entire window with a modern, energy-efficient product.

When it comes to all the random little leaks around electrical outlets, dryer vents, and other spots, caulk is your friend. Select a fire-rated, silicone caulk and apply it in any spots where you detect a leak. Smooth the wet caulk gently into place, give it a few hours to dry, and enjoy a more airtight home.

If the idea of identifying and fixing all your air leaks by yourself seems intimidating, turn to IT Landes in Harleysville. Our family-owned business has been a member of the community since 1929, and we remain committed to customer satisfaction. We can perform an energy audit for your home and help you reduce air leakage. We’re also happy to help with all sorts of other plumbing, heating, cooling, fuel oil, and geothermal systems in Montgomery or Bucks County. Find out more about our many helpful services by giving us a call today.