The heat pump is an air conditioner that reverses the process of removing heat from the inside of the house in summer to absorbing the heat from outside air and moving it inside in winter. It is effective by itself down to temperatures around 25 to 30 degrees Fahrenheit. At that point either a gas furnace or an air handler with supplemental electric heat will kick in and help heat your home. The Auxiliary Heat light on your thermostat will light. The heat pump will continue to operate during electric auxiliary heat. It will shut off when a gas furnace is energized. Emergency heat is a manual override option in the event your heat pump needs service.

Under normal operating conditions, the auxiliary heat is brought on automatically by the thermostat when the indoor temperature drops during heat pump operation. There are also times during cold wet weather that the outdoor coil may ice up and your heat pump will go into a defrost cycle. This is nothing more than reversing the process back to cooling mode. Cooling mode makes the outdoor coil hot and melts any ice. The defrost cycle should only last a few minutes and then return to heating mode. During the defrost cycle, your comfort system is in cooling mode and the supply air is cool. To offset this cool air, the auxiliary heat will be energized during defrost. A mist or fog may be visible during defrost.

The heat pump is effective in many applications. In all electric applications, the heat pump may consume less energy than an electric furnace or air handler using resistance heat. Why? Because it can deliver the same amount of BTUs as electric heat using less electrical input than the electric heat. In moderate climates, it lessens the need for the purchase of a separate gas furnace, as the savings that natural gas yields may not be as advantageous as in colder climates, since there is less frequent use of the furnace in milder climates. Of course the heat pump can be matched with a gas furnace where preferred. The heat pump can operate in the milder temperatures when the gas furnace may tend to short-cycle.

To determine which system would serve your specific comfort needs, a local independent Trane dealer should perform a Load Calculation on your home and then estimate the cost of operation for the different combinations of equipment.