7 Heating System Noises and What They Mean

woman hearing strange noises
February 10, 2021

If you’ve lived in your Shenandoah Valley home for any length of time, you likely know the sounds your residential heating system makes when it first turns on, while it’s running, and when it turns off. This means that when your furnace, boiler, or heat pump starts making a sound you’ve never heard before, you’re going to notice it right away.

When your heating system is making an odd clanking, banging, buzzing, rattling, or thumping sound, there’s clearly something wrong, but a strange noise can range from “slightly irritating but not a huge deal” to “you need heating repair right away to prevent a breakdown.” Today, we’re going to take you through a few of the more common sounds that heating systems including furnaces, boilers, and heat pumps can make when they aren’t operating correctly and explain what could be going on.

1. Thumping/Booming (Furnace)

A thumping or booming sound coming from your furnace could be caused by a gas buildup in your system, created by dirty burners that are delaying furnace ignition. If your furnace makes a banging noise when it shuts off, it could also be the sound of your ductwork expanding and contracting as a result of air pressure changes when your system turns on and off.

2. Screeching or Dry Squealing (Furnace)

Are all the belts and bearings in your furnace properly lubricated? If they aren’t, you could start hearing a high-pitched squealing noise as parts rub together. Luckily, a furnace repair call can help get your heating system back in optimum operating condition again.

3. Whistling/Vibrating (Furnace)

If your air filters are clogged or have become dislodged, moving air in your HVAC system can create a whistling noise as it goes past the filter. Depending on where the whistling or vibrating sound is coming from, however, it could also signal a ductwork leak allowing air to escape. 

4. Banging/Clunking (Boiler)

Boilers have a few tell-tale sounds they make when they’re not working correctly as well! A banging or clanking sound from your boiler likely means it’s kettling—this happens as limescale deposits build up over time, which creates pressure in the boiler’s heat exchanger.

5. Gurgling (Boiler)

A gurgling sound from your boiler, on the other hand, is often a sign of air bubbles in your pipes. This can reduce water flow as well as general heating problems in your home. If this happens, it’s likely that you’ll need to schedule boiler repair with an HVAC professional to remove the air bubbles by draining water out of your pipes.

6. Clicking (Heat Pump)

Air source heat pumps run on electricity, which separates them from most furnaces and boilers, but all electric HVAC systems can run into their own problems. A clicking noise coming from the indoor component of your heat pump could signal an issue with your start capacitor, which sends electricity to the motor to turn your heat pump on. 

7. Hissing (Heat Pump)

Refrigerant is the lifeblood of your heat pump—it’s what your system uses to move heat in and out of your home. But if you develop a leak in your refrigerant line, your heat pump will eventually fail to operate, and refrigerant can be a health and safety hazard for you and your family. A hissing sound coming from your heat pump is usually an indication you have a refrigerant leak and you should call for service right away.

Get Help for Your Heating System from the Local HVAC Experts

No matter what kind of HVAC system you have, and no matter what kind of unusual noise it’s making, Excel Heating & Cooling can help you solve your heating and cooling problem and get you back on track again quickly. From furnaces making hissing noises to a heat pump that won’t stop rattling, our team of experts is here to help you get to the bottom of the issue.

Plus, with our preventative maintenance plans, we can help you stay on top of the heating and cooling systems in your home and avoid strange noises in the first place. That’s why, for reliable comfort and energy efficiency, homeowners from Harrisonburg to Waynesboro trust their homes with Excel. 

Worried about an odd noise coming from your heating system? Call 540-434-0030 or contact Excel today and schedule an appointment for quality heating repair near you.

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