Having a frequent problem with my furnace where I can hear it humming softly, yet no air is coming out of the registers and the house temperature slowly falls.

It seems that this state can continue indefinitely, however a reset of the programmable thermostat (paperclip reset) always resolves the issue and everything is fine....until it isn't. I find myself resetting the thermostat several times throughout each day and it can be quite cold in the mornings when this state has happened overnight.

If resetting the thermostat ALWAYS resolves this issue for a few hours could this indicate that I need a new one?

  • Thermostats are pretty inexpensive, and what you describe suggests that it's likely enough to be the issue that it's worth replacing.
    – HikeOnPast
    Commented Dec 12, 2020 at 20:10
  • What make and model is your thermostat, and your furnace for that matter? Commented Dec 13, 2020 at 19:58

1 Answer 1


If your thermostat has batteries, replace them. If your blower motor is just humming, it either has a dead pole or the capacitor needs replaced. If your furnace is more than 15 years old the capacitor may have lost value and needs replaced. A furnace tech can quickly test the capacitor and it's a cheap and easy repair.

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