Having a properly running HVAC system is essential for keeping a comfortable home in Houston, Texas. No homeowner wants to deal with a broken or malfunctioning climate control system and its potentially long-lasting consequences. However, if you catch issues before they become major problems, you’ll be able to get your system fixed and be good to go with little discomfort. One of the easiest ways to tell if something is wrong with your HVAC system is if it’s making unusual noises. Here are five of the most common concerning HVAC sounds and what they may mean for your system.


Rattling often means that there’s some sort of debris or item stuck inside your HVAC. If you only hear the rattling outside, it’s probably in your exterior unit. Check to be sure that there’s nothing sticking out of your exterior unit if that’s where the sound is coming from. Also, make sure there isn’t anything leaning against it.

If everything seems clear, you’ll want to call a professional. The item may be up in your ductwork or managed to work its way into the system itself. This can lead to long term damage, so it’s important to take care of it as quickly as possible.


Clanking is another common sound that points to problems with your HVAC. Humming is normal, but clanking is a whole other ball game. Clanking can be any number of things, but its source is typically mechanical: a loose blade, pipe, or motor fan. The sound is coming from two pieces of metal in the interior hitting each other, causing the metallic sound.

Obviously, this isn’t a great sign for the health of your HVAC. It can lead to breakdowns or serious damage. While it may not create issues immediately, it still needs to be fixed quickly. If you have a maintenance plan, this is an issue that is typically caught before it becomes a real issue as your technician will check all components to ensure they aren’t loose.


Hissing isn’t as dramatic as the other sounds and typically won’t lead to a major breakdown. Hissing most often means that your ductwork is leaking, particularly if the sound seems to be coming from close to a vent. You may also notice reduced air flow and uneven temperature as the air intended for inside your home leaks away. Holes in your ductwork isn’t a DIY project, so be sure to call in an expert.

If the hissing is soft, it may be a poorly fitted filter. Double check to be sure your filter is sitting snugly in its holder without any big gaps.


This unpleasant sound is most often caused by a bad motor bearing or a bad belt. The sound is created by friction generated by two pieces of metal scraping against each other or from a bad belt grinding away. This is probably one of the most unpleasant sounds on this list and the onset will be sudden and irritating. It should be louder outside near the exterior unit versus inside your home.

Screeching is another issue that has to be addressed quickly in order to keep your system running and your home comfortable. This can lead to major breakdowns and expensive repairs if not fixed fast.


Clicking is a normal sound for your HVAC system. You should hear it right before your system kicks on or off. However, if you’re hearing a lot of clicking either during a cycle or with no air running, that may be a sign that something’s wrong.

If the clicking seems to be localized near the control panel or your compressor, there is probably something wrong with your system relay. This is part of the system that starts and ends the cycles of your HVAC and is hooked up to your thermostat. If there’s a problem here, your HVAC won’t get the signals to turn on as it should and you may have a stuffy home with poor airflow. Luckily, this tends to be an easy fix though you should still get it completed by a professional.

No one wants to deal with a broken HVAC system, especially during Houston’s hot summers. Hearing one of these noises? Give the HVAC experts at Maxx AC a call at (281) 338-2653 to set up a consultation today!

Image provided by Shutterstock

Pin It on Pinterest