IN YOUR FUTURE?
Regular furnace maintenance catches most issues before they explode into full furnace repairs, but many homeowners don’t keep up with the regular maintenance schedule.
Modern furnaces are built to run smooth and silent, and maintenance is typically performed when the furnace sounds good.
Knocking noises are most common in furnaces 15 years or older, and very dangerous. The knocking sound comes from small explosions of excess gas. Dirty burners delay ignition, gas builds up more than it should before igniting.