- Pool heaters use electricity to run their pumps, but they also use sun-warmed air, which means they don't need to generate any heat. A fan moves the warmed air through an evaporator coil that collects the heat from the air. The coil has liquid refrigerant in it, which absorbs the heat from the air. When this happens, it changes into a gas. Next, the gas is pumped into a compressor, which intensifies the heat.
- Once the gas is hot enough, it moves from the compressor to the heat exchanger condenser. This is where the water passes through. Cool pool water is pumped through the heat exchanger condenser, and as it passes through, the cool water takes the heat from the gas. The water becomes warm, and the gas becomes cool.
- Once the gas loses its heat to the water, it becomes a refrigerant liquid again. It is then pumped through something called an expansion valve, into the evaporator air coil, and the process to heat the pool water begins all over again.
