Noises Coming From Your HVAC? Here's What it Could Mean

If you’re searching for reasons your HVAC system may be making a particular noise, we’ve likely got your solution here! However, it’s important to keep in mind that hearing any odd noises from your HVAC will likely require a professional inspection to make sure your system is working at it’s optimized best.


For starters, if it’s been awhile since you’ve started up your heater for the first time of the season, clicking and even some popping noises is not something to be immediately alarmed by. This is because when you turn on your heater, the metal ducts are expanding because of the warm air being pushed through now. 

However, if clicking noises persist even after the first time you turn on the heat after some time, other causes could be an electrical problem. It could either be that the relay has stopped working properly or the contactor needs to be replaced.


A rattling sound coming from your AC unit is most likely a vent grille or something else has become loose or broken in your unit. Other possible reasons for this sound can also be:

Debris is caught in your AC: There may be some twigs or other material caught in the mechanism, so a quick and easy clean up may solve your problem.

Dirty air filter: If your air filter is clogged/dirty, it restricts air flow and can result in air ducts expanding and contracting, causing these noises and making your HVAC unit work harder. To prevent this, make sure you replace your air filter 2-3 months. Or, for a more cost effective option, you can opt for our eco-friendly AirThreds air filters, that are made of 100% polyester and are washable. Replacing your AirThreds are as simple as just throwing them in the washer ever.


If you are hearing a persistent buzzing , this could indicate that there may be a refrigerant leak or a compressor malfunction. Buzzing is another noise that indicates that debris is caught in your unit. 

A simple fix is to turn off the air conditioner for a few hours and then start it up again. Buzzing sounds can also signal an electrical problem. So if this happens a lot, a professional repair is likely what is needed.



If you are hearing hissing noises from your HVAC system, it is likely to be air leaking through the ducts.

If you hear a hissing noise and notice that your AC may not be cooling as effectively and also notice a leak, it is likely that you have a Refrigerant leak. These chemicals can be hazardous, so you should call a technician and refrain from using it.

The hissing noise can also indicate that a valve is leaking. As with most problems, if this isn’t fixed soon it could lead to bigger issues so it’s best to call a technician.

Squealing or Screeching

If you are hearing any screeching noises coming from your HVAC system, you are likely hearing one of your components beginning to fail. 

On the other hand, some units may make squealing noises and nothing is wrong – it is just the sound of your unit being used for the first time in a while. If this is the case, the noises will only last for the first few minutes upon turning on your AC.  However, if it persists longer than a few minutes, it could be a more serious issue and you should consult with a professional.

Although most sounds should be left in the hands of a professional, it’s great to inform yourself and familiarize yourself with your HVAC system so you can properly maintain it. The best way to keep your HVAC in great shape with little to no issues is through regular care and maintenance. Keep up with our blog to learn more tips and ways to make your HVAC the most efficient it can be!

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