Selecting the right heater depends on a number of factors. You need to consider the size of your pool or spa, the maximum temperature you would like to reach and how long you are willing to wait for it to heat up.

If you have a pool and spa combination, remember to consider both when deciding. Spas usually need to be heated more quickly and to a much higher temperature than pools, so select a heater with this in mind. If only a pool is being heated, it is not as critical to heat it quickly, so perhaps a smaller heater could be considered.

The gas energy consumed by a gas heater is measured in Megajoules (MJ) and the energy output rating is in Kilowatts (kW).

Smaller heaters are in the range of 60 to 100MJ and range through 250 up to 500MJ. The output ranges from 15 to 110kW.

Pool water is circulated through the gas heater which can run on either natural gas or LPG. The heat generated by the burning gas is transferred into the water which is then returned to the pool.

Heat pumps are designed to heat your pool by extracting ambient heat from the air – even in low temperatures. This heat is then transferred into a refrigerant gas which is compressed and heated further. The heat is then transferred into the pool water, and heats your pool. By using this process the heat pump units are very energy efficient with 80% of the required power coming from the air.