When Should You Worry About A Noisy Furnace?

Modern furnaces are relatively quiet. There are three sounds you'll typically hear from a furnace that's operating correctly: the draft inducer, the house blower, and the burners. Most of these noises should be inaudible unless your furnace is close to a living area or you're standing right next to your HVAC equipment.

Of course, all HVAC equipment can get noisier as it ages. If you hear some unusual sounds from your furnace, this guide will help you separate noises that aren't a big deal from ones requiring closer inspection.

1. Popping From Vents

Popping noises should be scary, right? While there are some situations where a popping noise might mean real trouble, it's probably not a cause for concern when you can hear it from your vents. If you hear some popping and cracking when your furnace first kicks on, you're probably hearing the sound of your metal ductwork expanding as the air heats.

Verdict: Don't worry about it. However, if the noises bother you, a contractor may be able to suggest some solutions, such as additional ducting insulation or rubber isolators.

2. Popping From Your Furnace

Unfortunately, popping noises from the furnace itself might be a much more severe issue. If you can hear popping while your burners are running, it may be a sign of incomplete combustion or even flame rollout. These problems can often be a sign of a cracked heat exchanger or another issue dangerous issue with the furnace's internal component.

Verdict: Stop using your furnace and call a pro. Combustion problems are hazardous enough to require immediate attention, and you shouldn't use your heating system unless you can confirm you don't have a flame rollout issue.

3. Squealing or Grinding

You'll commonly hear squealing noises while your blower is running or right after the furnace kicks on. These noises usually indicate a problem with the blower motor, such as worn-out bearings. If your HVAC system uses a belt-driven fan, you may also be hearing the first warning signs of the fan belt wearing down and preparing to fail.

Verdict: These problems aren't dangerous, but you shouldn't ignore them. If you hear these sounds consistently, it's best to contact a professional for an evaluation.

4. Buzzing

Buzzing from the furnace unit typically indicates an electric problem, although it can also be another component vibrating the metal housing. Try putting your hand on the housing to see if you can feel a vibration or stop the noise entirely. If there's no noticeable change, you may be hearing buzzing from a failing transformer or capacitor.

Verdict: Buzzing sounds are rarely critical, but you'll want a professional to look into the problem when possible. Buzzing electrical components are often close to failure, so investigating the issue now can save you from an emergency visit in the future.

For more information on when to seek residential heating repair, contact a company near you.