Furnace Making Strange Noises? Here's What Homeowners Should Know
Portage – September 25, 2026 -- Loud banging, screeching, or rattling from a furnace during winter often signals a mechanical or airflow problem rather than a harmless quirk, according to Bob Marquardt of Johnson Mechanical LLC in Portage, Wisconsin.
Banging sounds may point to delayed ignition
A loud bang at the start of a heating cycle can occur when gas builds up before burners ignite properly. Repeated delayed ignition adds stress to furnace components and can eventually damage the heat exchanger.
Rattling often traces back to loose parts
Unsecured panels, loose screws, or shifting internal components can create vibrations that grow louder during operation. Left unaddressed, the movement can gradually wear down critical parts inside the unit.