Your HVAC system is so much like your car. When it starts to make a loud noise, it rarely is good news. When your HVAC unit is operating normally, it should be relatively quiet and many of the sounds you hear will be normal. However loud and rumbling sounds can be a signal that your system needs professional attention. We have separated sounds out for you to listen for that indicate immediate action is needed!

1. Rattling from outside compressor and fan unit

— When the fan turns on in your compressor unit, it should NOT rattle. A rattling sound can indicate loose hardware or a failing motor. The louder the sounds, the more serious the problem can be. However, a squeal when the unit first starts is often a normal sound.

2. “Thwapping”

— If you hear a fast “thrawpping” sound when the blower is running, something may be stuck in the blades. There might be something inside the housing that is contacting the blower when it turns. If objects/debris are creating resistance, the motor can wear our abnormally fast.

3. Loud rattling, banging, clanking or banging noises

— These types of sounds are usually an indication of a problem with the blower assembly or motor. The rattling usually means a component is coming loose. The problem should be addressed before the part breaks/disconnects completely. If you hear loud banging sou when the blower is running, shut your system off entirely.

4. Squealing or screeching

— Squealing from the blower motor can be indicative of a bad belt or motor bearing problems. While belts are not normally expensive, they should be replaced before they break.

5. Repeated clicking sounds

— Clicking noises ARE normal when HVAC units turn on and off. If you hear repeated clicking coming from outside the compressor, a relay may be defective.

If you hear any of these sounds it would be best to call us! (262) 784-8889 or visit us online at

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