Pool water is moved by means of the pump from the pool, through the filtering system and then through the heater where the warm water is discharged back to the pool. The water is heated when it is passed through the unit's integrated heat exchanger where the heat from the combustion of the fuel is transferred to the pool water.

Gas pool heaters generally have the highest operating costs due to the higher pricing of fossil fuels and because of their relatively low operating efficiencies. In the recent past, gas pool heaters typically had efficiencies of 60% to 70%, but today standard gas pool heaters normally operate at an 80% efficiency. However, efficiencies approaching 95% are available in these units but have not gained popular use due to their high cost.

The most efficient way to operate a gas fired pool heater is to run it for a short period of time to bring the temperature of the pool water to the desired setting. For this reason, they are ideal for pools that aren't being continuously used. Although solar pool heaters and heat pumps require certain ambient conditions for their optimum performance, gas pool heaters can be used to raise the pool water temperature without regard to the weather or climate. The only requirement for gas pool heaters is the ability to connect them to a natural gas line or the siting requirements for an LP tank.

The Department of Energy provides a handy formula to size an above ground gas pool heater. It is expressed as: Pool Area X Termperature Rise X 12. The pool area is simply computed from the dimensions of the above ground pool and the temperature rise is determined by obtaining the normal ambient temperature of the coldest month that you will use the pool and subtracting this from your desired pool water temperature. It is based on a temperature rise of about 1 degree per hour and a wind speed of 3-4 mph. Refer to the associated Sizing Chart for Above Ground Gas Pool Heaters.

The water needs to circulate in order to move it through the required treatment processes. The swimming pool pump is used to do this. In your house, the water flows through the pipes because the pressure or motive force is supplied by the water company by a pump or the pressure created by a storage tank if you are supplied by a water utility company and by a pump if you are serviced by well water. The pool pump serves the same purpose. It provides a suction on its intake side to draw the water into it and discharges with a positive pressure to force the water through the trailing components and reture the treated water to the swimming pool.

After the water is discharged through the pump, it passes through a filter to remove and particulate matter that has settled into the poll. Swimming pool filters generally use sand as the filtering media, although cartridge and grid type filters are also commonly employed. Filters operate by a mechanical action and do not alter the water chemistry, but simply remove the solid impurities.

Many owner opt to install a pool heater to expand their swimming pool season, and this component is generally next in line. Above ground pool heaters are generally use gas, either natural gas or LP gas, as their heat source. However, swimming pool heat pumps are gaining popularity due to their lower operating costs. Electric resistance heaters are not as common as they once were due to the increased cost of electricity. Although solar panel pool heaters offer lower operating costs due to the fact that they don't need an energy source other than the sun to heat the water, they are not as popular with above ground swimming pool owners due to their high capital costs and the space requirements of the panels themselves.

Once the water has exited the heater, it is next passed through the chlorinator for disinfection purposes. Although some form of chlorine can be manually added, an electronic chlorinator automates the process and eliminates the need to constantly monitor the water chemistry and deal with harsh chemicals. Electronic chlorinators also use common salt that is converted to chlorine by the unit to save on operating costs.  This chlorination step is critical for the proper destruction of bacteria and virused whether you choose to automate the process with a chlorinator or add the chlorine via a manual process.

Although the absolute minimum requrements to maintain your pool can be achived with only a pump and a filter, the addition of an above ground swimming pool heater and an electronic chlorinator will extend and better maintain a healthy and happy pool environment.