Thank you for the answer kc. Yes a new digital thermostat during summer and I have it set for central heat and air. Perhaps this actually IS a heat pump but I don't recall the outside compressor coming on last winter or '06 (we moved in this new modular home in Aug '06) in fact, I actually had the compressor covered last year until the cover blew off. Maybe it was not the wind that blew it away but the compressor fan. How do I tell the difference between cent air and heat pump?:eek:

Usually the terminal designations will give a clue, or look up model number on manufacturer's website. Try this: temporarily disconnect and insulate the wire connected to "Y" at the thermostat, plug the outdoor disconnect back in if you pulled it out earlier, and try the heating again. If the outdoor unit is not running you probably have a heat pump thermostat.