Reasons Your HVAC System Might Be Making Noise After It Turns Off

When your HVAC system is working hard to control the temperature in your Southlake home, a little noise is to be expected. However, it can be disconcerting when the system turns off, and you continue to hear it making noises. The good news is that most of these noises are quite normal and are not a cause for concern. To help you decipher the noises that your HVAC system makes, here is a comprehensive guide to HVAC noises from your friends at Texas Pride Heating & Air.

Closing Dampers

If you hear a slamming noise after your HVAC system turns off, it could be because you have automatic dampers that are closing. Automatic dampers help you heat and cool your home more efficiently because they divide your home into zones that you can heat or cool individually. This means that your system doesn’t have to work as hard to maintain optimal comfort in your home. When the system is operating, the necessary dampers open to allow air to the correct zones. However, when the system turns off, the dampers close in order to prevent unconditioned air from flowing from room to room. When they close, they sometimes make a slamming noise, especially if they aren’t properly calibrated.

Draining Condensation

It can be disconcerting to hear water dripping in your utility area. However, if your HVAC system has just turned off, there’s likely no reason for concern. When your air conditioner runs, it pulls humidity from the air. This liquid water, known as condensate, flows out of the condensate pan and through a drain that exits your home. Although most of the water drains away while the system is running, a small amount may continue to drain after the system turns off. If you hear dripping water in the winter, you may have an efficient two-stage furnace. These furnaces create condensation during the second stage of energy extraction. However, if you hear dripping water for more than a few minutes after the system turns off, you may want to call Texas Pride Heating & Air to be on the safe side.

Moving Metal

Central HVAC systems rely on a system of ducts to get conditioned air where you need it. In most cases, these ducts are made of rigid metal. Since metal is an excellent conductor of heat, the temperature of your home’s ducts changes often. In the summer, the ducts heat up as the warm ambient air that surrounds them heats them from the outside. Then, when the air conditioner turns on, the ducts cool down from the inside. In the winter, this process also occurs, just in reverse. When metal changes temperature, it can expand and contract. As it’s doing this, you may hear banging, thumping, or popping noises coming from your vents or central HVAC system. While these sounds normally aren’t a problem, it’s good to have Texas Pride Heating & Air inspect your ducts every few years to ensure that the changing temperatures haven’t caused any gaps or cracks in your ductwork.

Rattling Air Filter

Keeping a clean air filter in place is a great way to protect your HVAC system and improve your home’s indoor air quality. The only downside of air filters is that they can sometimes make strange noises when your HVAC system turns off. If the air filter is sized perfectly for the filter opening and fits in it tightly, you likely won’t notice any sound coming from the air filter at the end of a heating or cooling cycle. However, even a slight gap around the perimeter of the air filter will allow the filter to move slightly in the enclosure.

When the system is running, the incoming air will pull the air filter against the filter housing. Then, when the system shuts off, the sudden lack of air pressure will release the air filter, causing it to settle in the frame. This can result in a crackling noise that lasts for a few seconds. We recommend using a paper towel to fill the gap around your air filter to ensure there aren’t any small gaps where dust could sneak through.

Taking Care of Noisy and Quiet HVAC Systems

At Texas Pride Heating & Air, we take our customers’ concerns seriously. When you hear a strange noise coming from your system, we’ll work to identify and repair the cause so that you can have a quiet HVAC system again. We also install air conditioners, repair furnaces, install insulation and indoor air quality products, and perform commercial HVAC maintenance. Since our founding, our excellent service has allowed us to maintain an A+ rating with the Better Business Bureau, and we consistently receive five-star customer reviews. To learn more about your HVAC system, contact us at Texas Pride Heating & Air today.

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