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Is Your Glendale HVAC System Making Strange Noises? Here’s Why

close up of a central ac

You often don’t think about your Glendale, AZ HVAC system till it stops working or starts to run loudly. After all, your HVAC system typically does its job quietly or with only slight background noise that you can easily ignore.

But what if the noises are strange, like clanking, rattling, or grinding? As you continue reading, you’ll learn the common types of HVAC noises, why they happen, and how you can prevent a noisy HVAC system. Call us at 1 (480) 626 4753 to check your system if your HVAC makes strange noises.

Common Types of HVAC Noises

An HVAC system with a problem typically makes various noises, from rattling to clicking. Read on to learn more about them.

Banging, Clanking, Thumping, or Rattling 

When you start hearing banging noises in your HVAC system, the chances are high that your compressor has an issue. If the parts of your compressor become unfastened, you’ll start hearing banging sounds when you activate the HVAC system.

The detached components hitting your compressor’s exterior framing cause rattling noises. Your UFirst Heating and Cooling Services professional will be able to fix this for you. 

Screeching or Squealing 

Screeching sounds often result from a malfunctioning fan motor in your outdoor condenser unit. Also, if your condenser system has a broken motor, you’ll likely hear squealing sounds. Another reason for these worrying sounds is a damaged blower fan motor in your house. Your best bet is to have a professional check your system to determine the root cause.

Buzzing, Vibrating, and Humming 

There might be an electrical issue if you hear buzzing or humming noises in your HVAC system. One of the most common reasons for a humming noise is a defective contactor relay switch. Buzzing noise may indicate loose fan blades or a faulty fan motor.

An obstruction near the copper lines connected to your system and dirty condenser coils can also cause buzzing. You should investigate either sound since they indicate a serious underlying issue. Call your HVAC technician for a tune-up without delay.


Often, these sounds begin after dirt and debris make their way into the fans of your HVAC system or inside your furnace’s blower motor. When these particles make their way into your AC unit’s mechanical parts, they cause friction, hence wear and tear.

It needs to be quickly dealt with by a licensed HVAC technician as the end result could be your entire AC unit breaking down. 


A dripping sound isn’t common so if you hear continuous dripping in your AC unit, your HVAC system likely has duct or refrigerant leakage.


Often, you’ll hear clicking at the start and end of your HVAC cooling cycles. However, persistent clicking from your air conditioner may indicate a flawed thermostat.

Removing and replacing a thermostat is a complex process. Fortunately, our team of professionals at UFirst Heating and Cooling has the necessary experience to ensure this issue is dealt with properly!

Why Is Your HVAC System Making Strange Noises?

One of the best ways to avoid unusual noises developing is by performing regular maintenance. If possible, schedule a maintenance routine for your HVAC system every year. Your UFirst HVAC technician will check your entire air conditioning unit and spot minor issues. These can include loose bearings, defective belts, and refrigerant or duct leakages.

In the long run, it’s best to figure out what’s wrong with your HVAC and deal with it early enough. That way, you save on extra costs that you’d have used on significant repairs in the future. Contact UFirst Heating and Cooling Services to schedule your HVAC maintenance today.