Why Is My Furnace Making a Strange Noise?

Close up of annoyed young latin American girl, closing her ears with fingers. She is looking angry, she is in a casual t-shirt on pure background.

A loud noise from your furnace is more than just an annoyance: it also may be a sign of a serious problem. Unusual noises from your furnace can mean the unit is somehow damaging itself, or even posing a danger to your home and anyone nearby. As such, don’t ever ignore noises from your furnace!

We’ve put together this short list discussing some of the most common noises and what may be causing them.

Remember, when in doubt, call in a professional. Troubleshooting the issue yourself may save you a buck, but also can be dangerous and unsafe.

Whistling Noises

A whistling furnace is one of our most common customer complaints. This can be caused by a variety of different components, but it’s always a result of air moving fast through a small hole or area. As an example, there may be holes in the duct. Examine the area around the duct and the furnace near the blower, as these are common spots for whistling holes.

A dirty filter is another cause of whistling. If the filter is too clogged to draw air, it will end up sucking air from elsewhere — like tiny holes in your duct. Take out the filter to see if it fixes the whistling. If it does, toss the filter out and replace it with a new one. Never leave in a dirty filter that’s causing whistling.

Rattling Noises

Rattling noises are a result of excessive vibration from the furnace or one of your ducts. Walk around the furnace and listen close to try to locate the source of the sound. If it’s a loose duct, you can try to secure it with duct tape or additional screws. If the furnace itself is vibrating, you could try adding a rubber pad under the furnace itself. Use a crowbar to lift it an inch or two to slip the pad in.

Rumbling Noises from Gas or Oil-Fired Systems

Rumbling noises can be an indicator of a very serious issue. It could be a sign of a carbon monoxide leak, which is an odorless gas that can be lethal to both humans and pets. If you hear a rumbling noise from your furnace, don’t take any chances and turn the unit off immediately. Your best bet is to call a licensed HVAC professional. It could be a less serious issue, but it’s not worth taking the risk.

If you’re hearing any worrisome noises from your furnace, call Great Dane today for professional advice and timely service.

Need HVAC Service?

Contact the experts at Great Dane Heating & Air Conditioning.

Call us at 586.790.2604!