I purchased a home that has ac and a heat pump, the outside temp is around 20 degrees and the pump is running. A neighbor informs me that a heat pump should not be running at these temps. Is this correct. And if it is correct where can I correct the setting? Is at the Thermostat or on the furnace?

I purchased a home that has ac and a heat pump, the outside temp is around 20 degrees and the pump is running. A neighbor informs me that a heat pump should not be running at these temps. Is this correct. And if it is correct where can I correct the setting? Is at the Thermostat or on the furnace?
Normal operation for a heat pump. Nothing to worry about...

A heat pump really looses it's efficiency arounf 25 degrees and below, but even if it is only giving a little heat is probably cheaper than the resistive heat running by it self. You could have a contractor install an adjustable low ambient cut-out switch if it really bothers you, or when it is below 20 just turn the stat to emergancy heat.