HVAC System Is Loud

We don’t tend to think about our HVAC system every day. Generally, we don’t consider our HVAC system unless it breaks or is running loudly. For the most part, an HVAC system will be very quiet background noise that’s easy to ignore. An HVAC system usually won’t run loudly unless there’s a problem.

Your HVAC system, if there’s a problem, may make several different noises. You may hear a buzzing noise, a popping sound, or even clanking. When your HVAC system is making unusual sounds, you should never ignore it.

Do you know why your HVAC system is so loud? We rounded up the most common noises you’ll hear from your HVAC system and what you need to do to fix them. Plus, we’ll tell you the #1 way to prevent a noisy HVAC system.

Grinding Noises from HVAC

Grinding noises can be caused by dirt and debris making their way into the fans on your air conditioning unit or into the blower motor of your furnace. It can also mean that dirt and small rocks have made their way into the mechanical components and are causing friction. This could cause your entire system to break down if not repaired quickly.

HVAC Screeches & Squeals

If your fan belt is wearing out, you may get a squealing noise while your HVAC system is running. Your motor may also need lubricant. HVAC motors require a very specific type of lubricant. If you are more comfortable with having an expert take care of it, an HVAC technician would be happy to help.

Clanks & Bangs

Generally, clanks, bangs, and rattling sounds mean that something is loose inside the HVAC system.

If you hear rattling, bangs, or clanking inside your home’s indoor HVAC system, something may have been knocked loose or broken. Often, this means a part got loose inside the blower. The louder the rattle, the worse the situation. If the rattling is loud, turn off your HVAC system and contact an HVAC company.

One of the most common sounds we get contacted about is a rattling noise in the HVAC system’s outdoor fan unit or outside compressor. Unfortunately, rattling noises often mean a bearing is coming loose or a component is failing. If you hear a rattling sound from your fan unit or compressor, you should call an HVAC technician to repair these as soon as possible.

If you hear bangs and clanks in your ducts, it’s also possible that something is stuck up there. This can be as mundane as debris from a storm or a squirrel that got lost. If you hear a repeated rattle in your duct, it may indicate that a portion of your air duct is coming loose.

Crashing Noises

Similarly, a crashing noise may indicate that part of your air duct has fallen off.

Is Your HVAC Rumbling?

Does it sound like a low pitch thunder is coming from your HVAC system? It might be time for a duct inspection, as something may have found its way into your ducts.

A frequent rumble can also indicate that the heat exchanger in your furnace is breaking down and may need to be replaced soon.

Dripping Noise

While not super common, if you hear a dripping noise in your HVAC system, it may be that there’s a refrigerant leak or a leak in your ducts.

Explosions & Booms

A booming noise doesn’t necessarily mean your HVAC system is exploding. But you should still get a specialist to check it out. The noise is likely caused by carbon particles and gas that had built up and combusted.


Buzzing is generally a noise that should be checked out by an HVAC specialist. Buzzing can be caused by the HVAC’s compressor malfunctioning or a loose part vibrating while the unit runs.

A buzzing noise can also be caused by bees in your air duct system. Sometimes, during seasons of low use, bees will find their way in and build their hives in the air ducts.

Hissing Noises from AC Unit

If you hear a noise that sounds like someone saying a long “s” sound, check your AC compressor. Check to make sure it’s not a refrigerant leak. If it’s not, it may mean that high pressure has built up in your AC compressor, causing a pressure lock. Either way, these are not issues you can DIY-repair. It’s best to contact a trustworthy HVAC technician.


When your HVAC system emits a high-pitched scream, turn it off as soon as possible. This can mean that high pressure is building up in your HVAC system and may explode.

How To Prevent A Noisy HVAC System

The best way to prevent a noisy HVAC system is regular maintenance. With regular maintenance every year or so, an HVAC technician will inspect your entire HVAC system. They will be able to spot minor problems such as a loose bearing, a bad belt, or a small refrigerant leak. By catching those issues while they’re small and easy to fix, you’ll save money on large-scale repairs later. You can also avoid a potential emergency such as a house fire or carbon monoxide leak.

HVAC Maintenance with J.A. Bertsch

Family-owned and operated, J.A. Bertsch is the most trusted HVAC contractor in North Idaho. Our licensed technicians receive continuous training on the latest advancements in the field. We also make sure they are equipped with the tools to service any type and model of HVAC system.

Over the years, our skilled technicians have seen it all. During our maintenance appointments, we’ll inspect your HVAC system, repair minor issues, and explain major issues. We will also give you an estimated cost for fixing the issues in your HVAC system.

Contact us today to set up an appointment at (208) 635-5480!

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