Why Does My HVAC System Make Strange Noises?

Common HVAC Noises and What They Mean

When your HVAC system starts making unusual noises, each sound can point to a different underlying issue. From rattles to hisses, let's break down some of the most common noises and what they might be telling you.



1. Banging or Clanking

If your HVAC system is making a banging or clanking noise, it's usually a sign that something is loose or broken.

• Loose Parts: When components inside your unit, like the fan blades or motor mounts, become loose, they can bang against other parts of the system.
• Broken Compressor: If the banging noise is coming from outside the unit, it could be a sign of a failing compressor.
• Imbalanced Blower: When the blower fan gets imbalanced, it can produce clanking sounds as it wobbles while spinning.

These noises are often a cry for help—your system could be nearing a complete breakdown. It’s a good idea to call in a professional technician before things get worse (or louder).

2. Hissing

A hissing sound coming from your HVAC system is typically a sign of escaping air or gas. Here’s what might be happening:

• Refrigerant Leak: If the hissing is coming from your air conditioning unit, it could indicate a refrigerant leak. This is a serious issue as it not only affects your system’s efficiency but can also pose health risks.
• Duct Leaks: Hissing can also occur when there’s a leak in your ductwork. Air escaping through cracks in the ducts reduces the overall efficiency of your system.
• Internal Valve Leaks: Sometimes, a hissing sound could point to issues with the internal valves or expansion valves in your unit.

Hissing is never a sound you should ignore. Whether it’s leaking refrigerant or escaping air, prompt attention is required to avoid further damage and skyrocketing energy bills.

HVAC Sounds You Should Never Ignore

While some noises may just mean your system needs a little TLC, others can signal more severe problems. Let’s explore some of the worst offenders in the sound department.



1. Screeching or Squealing

If your HVAC system sounds like a squeaky shopping cart, it’s usually related to the blower motor or fan.

• Worn Fan Belt: If the fan belt has worn out or become misaligned, it can create a high-pitched squealing noise.
• Dry Motor Bearings: The motor in your HVAC system has bearings that can wear out over time, causing them to screech when they need lubrication or replacement.

Ignoring these noises is like ignoring a crying baby—it’s only going to get worse. And just like a crying baby, your HVAC system needs attention fast to avoid a major breakdown.

2. Rattling

Hearing a rattle when your system turns on? This one’s pretty common, especially in older systems.

• Loose Panels: Sometimes, the panels or covers on your HVAC system can become loose over time, leading to a rattling sound.
• Debris in the Unit: If leaves, sticks, or other debris get into the outdoor unit, they can cause a rattling noise when the system starts running.

While rattling might not seem like a big deal, if debris is involved, it could lead to more significant issues if not addressed.

When the Noise Isn’t Normal: What Should You Do?

At this point, you’ve heard the clanging, hissing, and rattling, and you’re probably wondering if it’s time to panic. Don’t worry—we’ve all been there! The important thing is to know when to call in the pros and when a DIY fix might suffice.

1. Check for Simple Fixes

Before calling a technician, check for a few basic issues that you might be able to handle on your own:

• Tighten Loose Screws: Sometimes, those rattles and clanks can be fixed by tightening a few screws or panels that have come loose.
• Clean Around the Unit: Clear away any leaves or debris that might have found their way into your outdoor unit.
• Change the Air Filter: A clogged air filter can cause your system to overwork itself and produce unusual noises.
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2. Call a Professional HVAC Technician

If the noise persists after you've checked the simple fixes, it’s time to call in an expert. Some issues, like refrigerant leaks or motor problems, require professional tools and knowledge. Trying to DIY those could lead to more expensive repairs down the road. Plus, if you're hearing any hissing or screeching, don't delay—these noises could indicate a serious issue.

Preventing Future Noises: HVAC Maintenance 101

The best way to avoid strange HVAC noises in the future is through regular maintenance. Just like you wouldn’t skip an oil change for your car, you shouldn’t skip HVAC tune-ups!



Here are a few maintenance tips to keep your system running smoothly:

• Regular Filter Changes: Clogged filters not only reduce efficiency but can also cause your system to overheat, leading to noise issues.
• Seasonal Inspections: Schedule HVAC inspections twice a year—once before summer and once before winter—to catch potential problems early.
• Lubricate Moving Parts: During inspections, ensure that any moving parts in your HVAC system are lubricated to prevent squealing and screeching sounds.

Keeping up with regular maintenance won’t just quiet down your noisy HVAC system—it will also extend its lifespan and improve efficiency.

Call Ky and Rob's HVAC Plus for Professional HVAC Services in Roy, UT

If your HVAC system is making strange noises and you’re not sure what to do, let the pros at Ky and Rob's HVAC Plus take a look. Whether it’s a minor tune-up or a complete system overhaul, our team of certified HVAC experts is ready to get your system running quietly and efficiently again.

From HVAC installation and maintenance to mini-splits, heat pumps, and commercial HVAC services, we’ve got you covered. Contact us today at (385) 600-2750 for professional HVAC services in Roy, UT, and the surrounding areas. Don’t let those strange noises get any louder—call us now!

Remember, HVAC problems never fix themselves, but we can help you avoid costly repairs with prompt service and maintenance.

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