Taking care of the ductwork within your home is a vital part of keeping your HVAC system in proper working order. The best HVAC system in the world is useless without clean and functional air ducts to deliver cool or warm air to every room in your home. Here are seven signs that indicate your ductwork requires repairs or replacement.

1. Low Airflow

Hold your hand over any vent in your home. If the air pressure isn’t nearly as strong as usual, it may indicate a crack, hole, open seam, dent, or other damage in your ducts. Our professional HVAC technicians will be able to pinpoint the cause of the problem, repair the issue, and improve the airflow throughout your system.

2. Noises

Properly installed, high-quality air ducts should be completely silent when your HVAC system is in use. One exception is when your air ducts make a quick bang or pop noise shortly after the system kicks on. This noise is caused by the metal expanding or contracting due to the sudden change in temperature and is usually nothing to worry about. If the noises continue throughout the cycle or you hear new noises from the ductwork, this could point to duct issues.


If you hear a scratching noise within your ductwork, this is likely due to an animal in your walls or ducts. Squirrels, chipmunks, raccoons, rats, and even opossums frequently make nests in and around air ducts. These areas are warm in winter, cool in summer, and provide a dark and secluded location that is perfect for rodents if they manage to get in. Animals will scratch up and rip holes in your air ducts while making these nests. Additionally, they pose a health hazard to your home by bringing in fur, dander, fecal matter, and bacteria.


If you hear a buzzing noise coming from your air ducts, there’s a high chance that an infestation of insects is the source. Bees, wasps, cockroaches, and flies are the most common insects that like to nest in and near air ducts. Even small openings, such as punctures and torn seams, can give insects a perfect spot to infiltrate your ductwork. If you suspect you have insect problems in your air ducts, it’s best to contact a pest control professional immediately. The insects pose a health and safety risk to anyone attempting to evaluate and repair the ducts without removing them first.


A rattling noise is often the result of loose parts. If sections of the ductwork are not securely connected, they may rub or collide with each other, creating a rattling sound. Additionally, debris in the ductwork may move around when the HVAC system is active and produce a rattling noise.


Constricted airflow is the most common cause of whistling noises in air ducts. If your ductwork is badly damaged, extremely dirty, or clogged with debris from animals or insects, it could obstruct the airflow enough to produce a whistling noise.

Loud Persistent Banging

While a small bang at the start of each season is a fairly normal sound in your ductwork to make, loud, persistent banging is a more concerning issue. Loud banging noises are also most commonly caused by temperature fluctuations within the ducts. However, only abnormal fluctuations will cause persistent banging noises.

Several things could provoke these fluctuations. A clogged filter could cause the system to kick on more frequently and for longer periods of time, creating extended periods of heat or cold in the ducts. Poor insulation around the ducts also makes it more difficult for the air ducts to cool off or warm up normally. A professional HVAC technician will pinpoint the exact cause of the temperature fluctuations and make the necessary repairs to eliminate the banging noises.

3. Increased Energy Costs

Keeping your air ducts clean and fully functional is crucial to maintaining an energy-efficient HVAC system. If you’ve noticed an increase in your energy bills, your air ducts may be to blame.

Dirty air ducts cause your HVAC system to work harder and longer to move heat or cool air throughout your home. Similar issues occur when your ductwork has holes, cracks, open seams, or other damage. Repairing or replacing your ductwork may help reduce your energy costs.

4. Inconsistent Heating and Cooling

A properly working HVAC system with good air ducts should spread warm and cool air evenly throughout every room in your home. If you notice that some rooms in your home aren’t as warm or cool as the others, it may be a sign of damage in your ductwork. Damage or clogging contained to an area of the ducts close to the vent of a room will only affect the heating and cooling in that room. To create consistent heating and cooling throughout your home, you will need to have that section of your ducts repaired or replaced.

5. Age

Most air ducts only last about 12-20 years before needing extensive repairs or full replacement. If you weren’t living in the house when the air ducts were installed, you can find a sticker with the installation date on the inside of the main panel of your HVAC system.

If you suspect the system is newer than the ducts, you can hire a professional HVAC technician to inspect the ductwork. They can either give you an exact age based on serial numbers found on the ducts or roughly estimate the age based on the condition.

6. High Amounts of Dust

Another indication that your ductwork is in disrepair is unusual amounts of dust accumulating quickly in your home. Dust buildup around the vents is a particularly telling sign. The cause could be as simple as a clogged or ill-fitting air filter. However, if those factors don’t apply, it could be a sign that your ductwork requires repairs or replacement.

Deteriorating ductwork has gaps, holes, and cracks that draw dust, pollen, dander, and other debris from the surrounding area into the circulating air. The dust and debris eventually get deposited onto the surfaces of your home. High levels of dust and air pollutants irritate allergies, asthma, and other respiratory conditions. Repairing or replacing your air ducts will help you and your family breathe easier.

7. Air Filter Clogging Quickly

Another method of detecting a problem with the ducts is by monitoring your air filter. If you notice that your air filter requires replacement more often than usual, it could indicate that dust and debris are leaking into your ductwork. Those particulates circulate and end up in your air filter.

If you have detected any of these symptoms, you can rely on our skilled technicians at Cowboys Air Conditioning & Heating to provide the best repair and replacement services for your ductwork. In addition to ductwork repair and replacement, we also offer repair and installation services for air conditioners, heaters, air purifiers, humidifiers, dehumidifiers, and more. For additional information on any services we provide to residents in and around San Antonio, TX, contact us at Cowboys Air Conditioning & Heating today.

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