Sounds like a heat pump to me.
It acts like a normal a/c unit in cooling and a reversing valve switches the direction of refrigerant flow when operating as a heat pump.
The hot discharge gas from...
Summary It all depends where you live -- what the air pollution levels are in your area, and what kinds of pollutants you use inside your house. One should at least inspect the filter every 30 days...
Absolutely, a heating and cooling contractor would probably be the best person to call to install a new heating unit. This installation is very technically demanding for a homeowner to attempt...