Both air conditioning units and heat pumps work identically when cooling. A refrigerant is circulated and alternately changes phase from liquid to gas and back to liquid when compressed. The refrigerant is past through a radiator looking condenser giving up heat to the outside, compressed and pumped to the evaporator inside the house. Air passing through the evaporator, another radiator looking device, transfers heat from the air passing through it to the liquid that in turn becomes a gas because of the heat transfer. That means that operation in the cooling mode is identical between the two units. Air Supply Heating & Air Conditioning delves further into this below.
Heat Pump VS Central Heater Air Conditioner Combo
But come winter a reverser valve in the heat pump switches the flow by turning the condenser into the evaporator and vice versa, turning it into a heat machine. In heating mode, the typical heat pump can only handle so much, down to freezing outdoor temperatures, then it needs help. But as the outside temperature is above freezing, the heat pump remains quite efficient. The help is in the form of resistance electrical stripes, like a toaster just on a larger scale. Electrical heat however is not as efficient as hydrocarbon burners.
Gas Electric Packaged HVAC Systems
Everybody knows that it is more efficient to burn a fuel and use it directly for heat. Therefore, many air conditioning systems are paired with a natural gas, propane or oil furnace. Natural gas for the cook top, home heating and water heating is more energy efficient than electrical power. In those areas in the southwest that are at altitude can experience cold winters and very warm to hot summers. The gas furnace for winter and an AC are the best and probably the most efficient compromise. The farther south and/or lower altitude the more sense a heat pump makes. As it will accommodate the milder winter temperatures. In those instances where the home is all electric due to lack of natural gas, the natural solution would be the heat pump. The other solution is a propane furnace and an AC unit.
What is a Good SEER Rating?
Though considered by many as a marketing gimmick, both heat pumps and AC unit are rated by their SEER rating. As these ratings are tested in a controlled climate their efficacy in real world operations is in doubt, but again the higher SEER rating the better the unit. The current US standard is SEER 13, but there are higher rated models available. Energy Star standards is SEER rating of 11-12 or higher. The higher the SEER rating the less power used per unit of cooling. Operating costs should run about $850 per year for a 13 SEER rated unit. About $300 per year in cooling mode for both units. Longer warm seasons will of course up the costs.
What is the Average Life Expectancy of a Heat Pump or Air Conditioner?
Life expectancy is 12-15 years for the heat pump and 15-20 years for the AC unit, remember of course that they do not run year around like the heat pump. Some recommend duct cleaning every year and of course you have the filter expense for either unit. Due in part to the dusty conditions here in the Las Vegas area you will need to change filters at least monthly. Longevity is higher with the AC unit, after all it only runs during the summer, where the heat pump operates the year round.