We have Trane XB80 that's three years old. This past fall we installed a Hunter programmable thermostat model number 44360. The wiring on the thermostat was done correctly. We have natural gas heat. Our outside unit runs when we're using the heat. Is this supposed to happen and, if not, what could be the problem? This is the first house we've owned with central heat and air so we're kind of new at this.

Sounds Like The Outside Unit Is A Heat Pump.if It Is It Should Heat Your House Down To About 30 Degrees. If The Temperature Gets Below A Certain Point The Gas Furnace Takes Over.