The top 5 Furnace noises you shouldn’t ignore

by Team HomeServe |
Repair Furnace

Furnace noises are among the first warning signs your system will send you if an element is no longer working properly. While some sounds are common when you start your unit for the first time, you shouldn't ignore the persistent ones. You'll want to troubleshoot these potential issues before they become bigger problems - especially as the chillier weather begins to settle in.

If you hear one of these sounds coming from your furnace, your unit is likely telling you something's wrong:

1. Rattling

If an element of the furnace or ductwork is loose, you'll likely hear a rattling sound indicating that a part is out of place. If the whole unit is shaking, it's often due to a misaligned blower or loose motor mounts.

2. Chirping

This sound is normal when you turn your furnace on for the first time at the beginning of the season. However, if it continues to sound like there's a bird stuck in your furnace, your unit may need new fan belts.

3. Booming

If you turn on your furnace and immediately hear a booming sound similar to a car exhaust backfire, it's probably a sign of dirt buildup in the burner. It may not be a problem immediately, but it's worth having an HVAC technician give your unit a professional cleaning. Over time, this issue could potentially lead to a carbon monoxide leak. If the booming continues even after the initial startup, the noise may be due to poor duct installation or improper furnace sizing.

4. Squealing or screeching

Much like rattling, this noise can indicate that there's a loose or malfunctioning component of your heating unit. For instance, a loose or worn belt causes this type of noise. Have a professional adjust or replace this piece as soon possible, as it's a critical component for proper blower function. The problem may also be a shaft bearing that needs oiling or a blower motor that requires repair or replacement.

5. Clicking

This noise is normal when you first turn your furnace on or off, but consistent clicking is cause for concern. There may be a broken relay or failing ignition system. Your unit may automatically turn off, and you'll want to call a professional to troubleshoot the issue.

How do you check your furnace?

While most of these noises point to furnace problems that require the expert support of an HVAC professional, you can follow some inspection and maintenance best practices as a homeowner for proper furnace upkeep. Start by checking the filters to see if they're clogged, and replace them if necessary. In general, it's a good idea to replace your furnace filters every few months. You can also clear vents, ducts, grills and registers to remove dust or dirt buildup, which can prevent proper air flow and leave your furnace working harder to warm your spaces. Inspect for leaks coming from the unit. If you notice issues during your furnace inspection or home heating checkup, especially coupled with strange noises, schedule an appointment with an HVAC professional.

According to HouseLogic, you'll want to inspect your furnace twice a year - even if you don't hear any strange or unsettling noises. Keep in mind that it can cost $300 to $700 to repair each of the major components of a heating system, which means regular maintenance and inspections may help prevent major issues from creeping up when you least expect it.

Being prepared before home heating issues arise is always a good strategy. Plans from HomeServe can help with the costs of covered repairs. See what plans are available in your area.