How does a pool heat pump work? How do pool heat pumps differ from an electric pool heater, gas pool heater or solar pool heaters?
Pool heat pumps do use electricity, but they do not use electricity to generate heat. Electric pool heaters run electricity through a resistor of sorts and use the heat generated from that heating process to heat the pool water pumped through pipes wrapped around that heating element. Gas pool heaters use the same network of pipes to bring in cold pool water and transfer heat from a combustion chamber where the gas is burned to heat the pool water. Pool heat pumps instead use evaporator coils to either heat or cool refrigerant. A heat pump compresses the refrigerant in the compressor, heating it, before sending it to a chamber where the water circulates to be warmed. High efficiency pool heat pumps use scroll compressors while less efficient ones use reciprocal compressors.
The warmed water is pumped to the pool while the refrigerant is sent to an evaporator coil and expansion valve to expand and cool. Unlike the electric pool heater, the heat pump doesn’t generate heat in and of itself. The pool water never comes into contact with the refrigerant.
Pool heat pumps are sufficient for warming the pool water in mild to moderate climates or warming up pool water in the morning or evening; they can add two months to the swimming season and several hours of pool usage per day when it would otherwise be too chilly. And like some solar hot water heaters, the flow of the water can be reversed with some systems to cool down the water in very hot climates.
Pool heat pumps can be used even when you don’t have a natural gas connection or propane source. They are independent of weather conditions as long as it isn’t too cold to run the heat pump; most models simply cannot work when air temperatures are below 50°F. And the cooler the outside air, the more energy it has to use just to work, though its efficiency isn’t nearly as impacted by hot outside air. For colder climates, you should buy a pool heater, whether electric or gas.
A pool heat pump is the better choice if you live somewhere cloudy or constantly overcast that prevents solar pool heaters from working. The biggest issue with pool heat pumps is its low efficiency – it takes a longer time to heat a pool than an electric or gas heat pump, and it can’t warm the water as much as either of those types of pool heaters. Conversely, the heat pump is more efficient than an electric pool heater in mild climates, so you won’t drive up your electric bill in an effort to use the pool. Heat pump pool heaters also last longer on average than gas pool heaters.
Unlike gas pool heaters, a pool heat pump has an installation cost and no ongoing operating costs. Just install and run as if it were an air conditioner. Pool heat pumps have higher upfront costs than electric and gas pool heaters, but they can cost less over a long operating life.