Gas pool heaters, which burn either propane or natural gas, can maintain your pool at pretty much any temperature you desire. Want 90°F pool water over the holidays? No problem.
Well, actually there is a problem. The cost of both propane and natural gas has roughly tripled during the last 10 years. With propane now costing $3.00 per gallon or more, it can easily cost as much as $4,000 to keep a 14 x 28 Central Florida pool at 80°F on a year-round basis.
That said, the great advantage of gas is the ability to maintain any temperature in pretty much any weather. As long as you are willing and able to pay. This might be important if you must use your pool for therapeutic exercise. Even so, with today’s high and rising fuel costs, we recommend that a gas heater be installed only as a backup system to supplement a primary solar pool heater or pool heat pump when 85–90°F pool water temperatures are medically required.