FurnaceTroubleshooting2026-01-20
Furnace Making Strange Noises: A Sound-by-Sound Guide
Banging, squealing, rattling or rumbling each point to different furnace problems.
Furnaces make some noise, but new or loud sounds are clues. Here's what common furnace noises usually mean.
Banging, booming and rumbling
A delayed 'boom' on start-up often means dirty burners igniting late — a safety concern worth servicing. Rumbling after shut-off can be a dirty flame sensor or burner.
Squealing, grinding and rattling
Squealing usually points to a blower belt or motor bearing. Grinding means worn bearings — shut it off to avoid damage. Rattling can be loose panels or ductwork.
Key takeaways
- Address delayed ignition booms promptly — it's a safety item
- Grinding means shut down and call for service
- Tighten loose panels and duct connections
- Annual servicing prevents most noise issues
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