5 Signs You Have an Air Duct Leak

Air duct leaks are a common problem that can seriously impact your monthly utility bills, the air quality in your home and can lead to you needing an air duct repair. But how do you know when you’ve got a leaky air duct? To help you, we’ve assembled our top 5 signs that an air duct leak may be occurring in your ductwork.

#1: Uneven Heating and Cooling

If you’re noticing that certain areas of your home just don’t seem to get cold or warm when your HVAC system runs, it may be a sign of duct leakage. In houses with an air duct leak, you may be losing as much as 30% of the air passing through the system into the unconditioned spaces of your house like your attic or crawl space. This affects the system’s ability to effectively distribute cold or hot air to certain parts of your home, which results in uneven heating or cooling.

#2: Excessive Dust

If you’ve noticed that there just seems to be no end to the amount of dust in your home, it may be the result of an air duct leak. Air ducts are often placed in the unconditioned spaces of your home, like crawl spaces and attics. An air duct leak in a dusty attic or crawl space will allow dust to enter the system and be distributed throughout your home.

One problem with this, besides the unsightly appearance of dust on all of your furniture, is that dust negatively impacts your home’s indoor air quality. Dust that collects and settles in attics can contain environmental contaminants that are then spread throughout your home by an air duct leak. To avoid this, keep your ductwork sealed and your attic cleaned and free of dust.

#3: Rising Utility Bills

Your utility bills can be a good benchmark for whether your home’s energy efficiency is affected by leaky duct work. If you notice that your utility bills are higher, you may want to take the time to inspect your ductwork. Air leaks can allow a significant percentage, up to 30%, of the conditioned air passing through your ductwork to escape into your attic. That’s just money lost!

Estimates vary for how much of an impact that lost air has on your utility bills. In regions where air conditioning is continuously run, those leaky air ducts have an estimate to account for up to 35% of a home’s entire energy load. This means addressing those leaky air ducts is one of the most cost-effective ways to boost your home’s energy efficiency, particularly if you run your HVAC system regularly.

#4: Unable to Cool or Heat Certain Rooms

If you have rooms that just won’t respond to your air conditioning or heater, there’s a good chance an air leak in the ducts is the culprit. Duct air leaks rob your system of the air pressure needed to cool or heat areas of your home effectively. If you’re noticing it only in one room, it may be that the air leak is affecting only that branch of your duct system. 

Take a moment to assess the condition of that duct if you can do so safely. You’ll probably find a tear, frayed seal, or some other indication that a leaking duct may be occurring. Looking for these visual indicators is a straightforward method for how to check air ducts for leaks, but it won’t tell you the whole story. To determine how much your entire system is leaking air, you’ll probably need a professional assessment.

#5: Damaged, Brittle or Old Ductwork

If you’ve looked at your ductwork and noticed any damage, broken seals, or gaps between joints, you are almost certainly leaking air from your ducts. Many homes built in the 1980s and 1990s had ducts that leaked around 20% of the air passing through them when they were new. That number has only risen over the years, as sealants become less effective and ductwork suffers from the ravages of time. 

If your ductwork looks old and brittle or shows obvious signs of wear, consider having it professionally assessed. A quick repair, such as duct sealing or targeted replacement may quickly pay for itself by reducing the percentage of air lost from the system each time you turn on your air conditioning. If you want to avoid high air duct replacement costs, consider addressing the problem as soon as possible.

What to do if You Suspect a Leak

If you suspect an air duct leak, you’re probably wondering what to do next and how to check air ducts for any leakage. If you can do so safely, narrowing down the location of the leak and size of the leak can help you determine whether it is something you can repair yourself. Ductwork often passes through the attic, so be very mindful of your footing and safety if you choose to track down the leak.

Alternatively, call our team at Attic Construction! We offer air duct cleaning and repair services and help you determine the extent of the problem and outline possible solutions. 

Even if you repair yourself, it’s a good idea to have your air ducts professionally cleaned after a leak. While fixing air duct leaks will return integrity to the system, it won’t remove any contaminants that may have entered your system when there was a leak. Thorough cleaning after you seal up your system will ensure only clean air is passing through your system into your home.

Closing Thoughts

Finding and fixing air duct leaks can be a challenge, but for many homeowners, simply recognizing a problem with their air duct system can be a hurdle. Keep an eye out for common signs of an air duct leak, such as difficulty circulating cold air into certain rooms in your home, excessive dust throughout your house, or rising utility bills. 

If you suspect an air duct leak or simply want to have your ductwork inspected, contact our team at Attic Construction today! We’ve helped hundreds of homeowners address their ductwork problems, resulting in better energy efficiency, higher air quality in the home, and more comfortable conditioned spaces. To schedule an inspection or learn more about our services, contact us today.


  1. “Duct Dynasty*” https://www.buildingscience.com/documents/insights/bsi-074-duct-dynasty
  2. “Why You Need to Air Seal Your Home” http://www.greenintegrateddesign.com/blog/air-sealing-your-home
  3. “Air Duct Replacement Cost Guide” https://homealliance.com/blogs/air-duct-replacement-cost-guide#:~:text=The%20best%20is%20to%20call,you%20are%20going%20to%20use.


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