Question : Why does my gas furnace make a roaring sound?
I don’t turn on the heat too much (especially with today’s gas prices), but even with the heat turned off, sometimes my furnace flame seems to make a loud roaring sound. After awhile it goes back to its usual softer sound again.
I paid $ 89 for a service maintenance and cleaning the other day, and it still makes the sound. It makes the sound when the heat is off.
gas furnace prices

Best answer:

Answer by Fuzzy Zoeller
I think it has to do with the gas line. Pressure can fluctuate from time to time slightly, and when it changes, the flame burns bigger and makes more noise.