Liquid propane has the same disadvantages as natural gas, and it is significantly more expensive than natural gas. Fuel oil is readily available and can be delivered to storage tanks on the pool owner's property. Its cost varies depending on geographical area, but generally can equal or exceed that of liquid propane. Like other fossil fuels, fuel oil provides fast heat. Fuel oil heaters are not odorless, so it's best to place the fuel oil- fired pool heater away from the pool and recreational area.
Electricity is universally available.
Electric pool heaters are flameless and small. Electricity is the most expensive option for pool heating. In some areas there are peak time restrictions for heating swimming pools so pools must be heated during non-peak times only. In addition, all electric pool heating systems require special heavy duty electrical wiring and large amperage circuit breakers, making the electrical installation complicated and expensive.