Correct, Muley. Now, to contradict my esteemed colleague, Cowboy, there is a very good argument for leaving the fan motor running, even when the heat plant or a/c compressor are not running, and that is to prevent stratification throughout the home, particularly in the Summer when temps get very warm. I leave my fan motor running when the a/c is on, and find that my compressor runs significantly less frequently, even on the hottest of days, than when the system is on automatic. I don't consider the electric bill to be any higher than normal summer usage, but I do know that the house is a lot more comfortable both upstairs and downstairs (I have a 2,600 sq. ft. colonial). That being said, I also adjust my heat run dampers at the change of seasons so more of the volume is going UPSTAIRS in the Summer, and the opposite in the Winter. We also run our ceiling fans in reverse in the Winter to circulate the warm air that hugs the ceiling. I don't worry if the electric bill changes $5-$10 if I'm running these motors, because I feel my comfort is worth it. I'm sure I piss away more money than that each month on stupid stuff. Oh, I also have a new, backup furnace blower motor in a box next to the furnace should I need to replace it. I also have a new backup sump pump as well. These are important to me, as both items seem to fail on Sunday afternoon or during the night, both times when you pay a premium for the repairman, and when it's impossible to get parts.
. On or fan are for when you want it to run constantly & it bypasses the temp setting .
