Even in a very sunny country such as Spain, and especially in the south of the country where you find popular tourist destinations such as Malaga and Marbella, water temperatures in outdoor pools don't really rise to the kind of comfortable levels you would enjoy swimming in until late in the month of May.
If your outdoor pool is surrounded by buildings or tall trees for example, it might be even later in the year than that, so without heating the water in your pool to a comfortable level you are restricting the swimming season to just a few months of the year, usually June to September.
A big advantage of having a heated pool where owners of holiday rental property are concerned is that a pool heating system means that they can attract tourists outside of the usual holiday periods and as a result generate extra income, so the pool heat pump pays for itself eventually over time.
How Does a Swimming Pool Heat Pump Work?
A swimming pool heat pump works by transferring heat from the surrounding air to the water in your swimming pool. It is able to do this by a process of heat conduction where the air passes over an evaporator coil which contains a very cold refrigerant gas.
The air, being at a higher temperature than the refrigerant, passes some of its heat into the gas through conduction as it passes over the evaporator coil.
The warm gas is then compressed within a compressor unit which increases pressure within the system and this in turn increases the temperature of the gas.
At the end of this part of the process the gas, which was initially very cold, has become very hot.
The hot gas now passes through a condenser unit which is the part of the pool heat pump where the water flows through. As it flows through the condenser unit, the water takes some of the heat from the gas and increases in temperature, ready to be pumped back into the pool as warm water. It is this warm water that increases the overall temperature of your pool, allowing you to swim comfortably even during the times of the year when you would not normally be able to do so.
Now the really clever bit; as the water takes the heat from the gas, the gas cools and then passes through a metering device which reduces the pressure of the gas to normal (remember it was pressurised inside the compressor to increase its temperature), allowing the refrigerant to become very cold again.
The cold gas is then passed back through to the evaporator coil and the process starts all over again.