Our furnace blower is set to auto....it runs when the furnace is and is not calling for heat but the humidifier is on. This is a problem because the forced hot air system is blowing cold air which creates a constant draft in the house.

  • it should be on, but you can probably lower the speed of the blower fan to half or 25% of full on in the furnace's control panel.
    – dandavis
    Commented Dec 21, 2020 at 21:13
  • 2
    You could change the humidifier to only operate when the heat is on.
    – lordadmira
    Commented Dec 22, 2020 at 3:48
  • As @lordadmira mentions the control can be revised to only humidify while the fan is running. This is most often how residential systems are set up. Business like Florist than need tighter control and higher humidity keep the fans on to maintain the moisture. Clean rooms also do it but that is more for particulate control but again the humidity is controlled to tighter specifications than a home. the critical thing is you need air flow while the system is running. I usually have an air flow vane that is a safety to prevent humidification if there is no air flow.
    – Ed Beal
    Commented Dec 22, 2020 at 14:38

1 Answer 1


If Your fan is connected To your humidistat in the the ducts (it should be for best humidification control) when humidifying you need the fan to run or water will end up building up in the duct work.

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