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What’s That Sound? HVAC Noises You Need to Address

May 3, 2019

You don’t need to be an expert to realize that your HVAC noises system shouldn’t sound like a monster truck.

But if you’re not sure what that sound is that’s coming from inside the walls, or anywhere else from your home, Maryland’s HVAC service and repair professionals are here to tell you what kind of sounds to keep an ear on, so your home will continue to receive the ideal heating and cooling it needs.

This time of year, properly working heating and air conditioning in Maryland is essential for making it through these unpredictable weather patterns. When an unsettling noise comes from the HVAC system—especially an older one, homeowners might have something to worry about. Here is what you can listen for so you can take the steps necessary to ensure any HVAC problem becomes an HVAC disaster.


Screeching or squealing HVAC noises indicate that it’s either time to replace a belt, or there’s a problem with the blower’s motor system. If the belt snaps or the motor finally breaks, your system’s blower will stop working. Although belts aren’t a very expensive repair, it’s better to have them replaced before they snap. Also, check to see if your blower unit’s oil port is accessible—if it’s not sealed, adding some lubricant might be a quick fix for your blower’s screeching and squealing noises.


When you hear rattling coming from the HVAC system, it could mean more than one thing. If the rattling is coming from inside the home, it could be a problem with the furnace—if this is the problem, shut off your HVAC system, and call a professional.

If the rattling is coming from outside, it could mean that the problem is just a minor clog caused by dirt, grass, or twigs. The easy-to-fix solution is to shut down the power to your HVAC system and remove the debris. If you notice any damage to the compressor, fan, or coils, get in touch with a professional here(hyperlink).

A hissing noise might mean that air is escaping from your HVAC system—wasting air. If you hear the hissing noise coming from the walls, it means that your ducts are leaking--but find out for sure before hand that the hissing isn’t due to your HVAC system’s settings.


A simple humming noise is a good indicator that your HVAC system is running the way it should be. But if you hear banging and clanking, then that means something is wrong and needs to be addressed ASAP, even if it’s a small issue, like loose pipes or parts rubbing together.

When loose parts are banging and clanking together, there could be a serious issue to address. If not addressed correctly and in time, these banging and clanking noises can cost a homeowner a lot of money in system damage. If you notice excessive banging and clanking, turn the system off and call your technician.

When it comes to residential or commercial HVAC systems, MaxAir is the leading heating and air conditioning company in central Maryland. This spring, when you have no idea what kind of weather Mother Nature has planned for us, make sure your HVAC system is working at top performance, and be sure to address any disturbing HVAC noises coming from your appliances. For more information about how we can service you, click here.