My house was built early last year, and this is the first winter I'm in the house. The house has a RUUD RGFG 75K BTU gas furnace and matched A/C. I also have a communicating thermostat (501), which apparently can't control humidifcation function (but can control dehumidification). I also have a bypass humidifier on the furnace, with a manual control.
The trouble I'm having is that the humidifier doesn't seem to help much -- when it runs anytime the system runs it increases humidity levels 2-3% (from 22% RH to 25% RH at 25 deg F outside temp, and 70 deg indoor temp). The furnace is modulating with a variable speed motor, and while it tends to run for longish periods of time, it tends to run at a comfortable 400 CFM (low noise), at 40-50% capacity.
My hunch is that the airflow is too low for bypass humidifier to do much, and thus I'm just wasting water. Should I replace it with a powered humidifier? Do you think it would help resolve the problem?
The house is 3600 sq. ft, and has a second furnace in the attic covering the second floor. Similar problem there, though humidity is more reasonable at 30-33% RH under the same conditions.