Heat Pump or Furnace? What you Should Know Before Deciding

January 22, 2013

A heat pump or furnace will deliver warm, indoor comfort when the weather turns colder in the fall and winter months. Since each heat pump system employs a different method to warm the air, it is important to understand the respective features and benefits of both appliances before making a purchasing decision.


The gas furnace heating cycle is initiated by a relay that activates an inducer fan. When the air flow is adequate, a valve opens and releases a precise amount of gas, which is ignited by an intermittent pilot or a hot surface igniter. The gas warms a stainless-steel heat exchanger, and the blower draws air across the heated surface. Warm air moves through the building’s air distribution system while waste gas is exhausted outdoors through vent pipe.

Furnaces are rated according to the Annual Fuel Utilization Efficiency (AFUE) standard, which was adopted by the Department of Energy to facilitate an operating cost comparison between different furnace brands and models. Replacing an older furnace with an AFUE rating of 65 or less with a new 90 AFUE rated model can save up to 30 percent on annual heating expenses.

Over time, manufacturers have improved the reliability and safety of gas furnaces. Newer models use electronic ignition systems to eliminate the potential for standing pilot catastrophe. Two-stage, multispeed technology has improved efficiency, performance, comfort and also lowered noise levels.

A furnace installation is considerably less expensive than a full heating and air conditioning system, and the existing ductwork can usually be used for an A/C retrofit. However, the furnace combustion process yields harmful waste-gas byproducts, which can be deadly if not properly vented. It is important to have a furnace periodically serviced by a certified HVAC technician to ensure the integrity the burn cycle and to verify the heat exchanger is not cracked.

Heat Pumps

A heat pump operates in a manner similar to a conventional air conditioner. The refrigeration cycle is an ongoing process where heat is transferred from the inside of a building to the outdoor environment through the use of a refrigerant. The main difference in heat pump operation is the inclusion of a reversing valve, which allows the refrigerant to flow in the opposite direction for heating purposes.

In the A/C mode, a heat pump is only slightly less efficient than a conventional central air conditioner. However, in climates that consistently reach low temperatures near freezing, a heat pump’s performance is substantially degraded. While in the heating mode, heat energy is extracted from the outside ambient air and exhausted into the interior of the building. As the load rises, the capacity decreases as the unit struggles to remove heat from the colder, outdoor air.

In heat the mode, heat pumps are rated according to the Heating Seasonal Performance Factor (HSPF) standard. A higher HSPF rating indicates the equipment is more energy efficient relative to other brands and models.

Fortunately, the local climate in Baldwin County AL is relatively mild since the mean-low temperature rarely falls below 40 degrees Fahrenheit. The lack of extreme cold weather allows local residents to install either a heat pump or furnace. For those rare times when heat pump capacity is insufficient relative to the demand, an electric strip can provide supplemental heat.

A heat pump is generally considered safer than a gas furnace since it does not burn fossil fuels directly. There are no waste-gas byproducts onsite that require a ventilation path to the outdoors, and there is no threat of carbon monoxide entering the livable area. In regions where local electric rates are low, a heat pump may be less costly to operate when compared to a gas furnace.

Serving the Baldwin-Mobile area for nearly 50 years, the factory trained professionals at Keith Air Conditioning, Inc. can design a heat pump or furnace system tailored to meet the unique characteristics of your lifestyle and indoor environment.