I replaced warranty humidifier control. Rewired humidifier system for updated control. I found furnace temperature rise out of range! Found air filter clogged (1” pressure drop) due to use of cool mist atomizing humidifiers in the home. Explained operation of new control to customer. Current humidity: 34%. Ambient: -2. Moisture on windows. Suggestions: expect lower humidity in extremely cold weather. Air is currently at maximum humidity due to ambient conditions. Set blower activation switch on humidifier control to “on“ for maximum humidification. Consider dialing down humidifier control and extremely cold weather.