The difference between between a straight cool air conditioner and a heat pump system is difficult to see at a glance. The functioning differences between the two are hidden behind the access covers. A heat pumps extra piping, electronics, and controls all fit nicely into the same size package as their straight cool counterparts. For the cooling season, either type system operates on the same principles. In the heating season is where the operational differences occur. A straight cool air conditioner will not run the outdoor unit in heat mode, instead, it runs an electric resistance heater located in the air handler. A heat pump system is able to run the outdoor unit and reverse the direction of the refridgerant flow and pump heat into a living space. Heat pumps maintain the resistance heater as a back up when the weather gets very cold and either the heat pump needs a catch up boost or the outdoor coil needs to be de-iced from operating in the cold weather.
$500 to $1000 more for heat pumps (depends on the tonnage). An air conditioner (also refered to as a “straight cool”) have less components and so cost less when they are initially installed. From the installing perspective the complication is limited to only a few extra control wires. The time needed to complete the work and supporting materials to do the job installing heat pumps and straight cools are essentially the same. The price difference between the two types is due the extra piping, valves, switches and electronics hidden under the access covers of the heat pump. The initial cost difference varys, increasing as the SEER and BTU capacity increases.
Cooling costs are the major portion of electric bills in Florida. Due to our mild winters, heating season electric bills are usually much less then summer cooling bills. Even a small version of the electric resistance heater in a straight cool air conditioner uses more electricity than the whole air conditioner does in the summer, but due to our location in Florida the need for heat in winter is much less than the need for cooling. When comparing a 2.5 ton heat pump to a straight cool with a large 10KW (KiloWatt) electric heater the heat pump makes 3 times the heat and costs 1/4 of the electricity to run. An average heat pump efficiency starts to fall off at 40 degrees due to defrost cycles. At 25 – 30 degrees average heat pump struggle greatly, although high performing heat pumps can warm a home while outdoors is down to a chilling zero degrees. Our area of Florida rarely sees temperatures that would make a heat pump struggle.