When the system is on, both inside(blower) and outside (compressor)units are on.Neither one of the units shutoff. once the desired temp is reached.The outside unit is an Amana and in the inside unit, which is up in the acttic is a Lennox. I believe the thermostat is a Hunter heat pump thermostat. It has all the lights for the aux heat and emergency heat. Yes the thermostat is completely programable. Right now in texas it is not that cold, 50 at night 70 during the day. When the thermostat is set to 75 and its 70 in the house when you turn the system on the, aux heat kicks in and then when it reaches 75 the aux turns off. The complete unit inside and outside units stay on all night, but the house stays around 75 degrees.