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5 HVAC Sounds and What They Mean

Is the HVAC system in your Orange, Texas, home making strange sounds? While your HVAC system does make audible sounds as it runs, it shouldn’t make any that seem concerning. Any irregular sound that comes from your HVAC system could be a sign that it’s in need of a repair. Each noise will be different, and it’s important to know how to address them effectively. Here are five common HVAC sounds and what they mean for your system.


Modern HVAC systems feature highly precise machining techniques and parts that are all connected. Therefore, you shouldn’t have to worry about unusual noises coming from your unit. If you do hear clanking sounds coming from your HVAC system, it means there’s something in the unit that shouldn’t be there.

If you hear clanking, try to locate the source of the sound relative to where it’s coming from. If you think it’s coming from the vents, then this is less concerning. It just means that something is loose in your vents and can be easily removed. However, if the handlers are clanking, shut the system off immediately.

There could be any number of things that make your handlers clank, and if they are making a fuss, it’s something you should be careful about. The handler is where all of the moving parts are, including the fan. Shut the system down on your thermostat and have an HVAC technician come to look at it. Don’t try to retrieve the item while the system is still running.


Hissing is less of a problem when it comes to strange sounds, but it’s important to pay attention to it either way. Hissing usually means that there’s a medium-pressure leak somewhere in the system. This could mean your air conditioner has a leak where the refrigerant gas is seeping out. It could also be a leak in the drain system where air is getting in or escaping.

Either way, you want to look and see if you can find the source of the leak. Drain system leaks are easy to repair, but cooling system leaks require a technician to diagnose and repair them.


If you hear your HVAC system popping, it can be one of two things: a break in a wire or conductor where electricity is still jumping over or a moving part getting stuck on or hitting something. Either way, you want to shut it down and have it diagnosed immediately. This could indicate that something needs fixing. You should have your system looked at as soon as possible, and keep it turned off.


Squeaking is probably the least stressful of the strange noises to diagnose and fix. It usually just means that the moving parts are rubbing against each other. During routine maintenance, an HVAC technician will clean, recalibrate, and lubricate parts so that they run smoothly. The difficulty of service depends on where the squeaking is coming from. Parts like the drain pump and the coil are easy to clean. However, you shouldn’t attempt to do this on your own. The system needs a professional inspection since it may take some disassembly to fully address the issue.


Whistling sounds like an old tea kettle when it’s hot and steaming. If you hear your HVAC system whistling, that means you have a high-pressure leak somewhere. High-pressure leaks of any sort are a serious problem since they can change how the system works very quickly.

The most likely place is your cooling system, specifically the refrigerant line. If your system is losing refrigerant fast enough to whistle, you need to have it serviced right away. It’s losing its ability to regulate air temperature, meaning your system may run but won’t be able to work effectively.

At Thermacon Service Company Inc., we provide 24-hour emergency service to take care of any issues, including unusual sounds, you may be having with your system. Call us today at 866-797-1535 for professional HVAC repair services.

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