Florida's climate means most pools don't need a heater to stay swimmable May through September. But for spring, fall, and the occasional cold snap that drops overnight lows into the 40s and 50s (common as far south as Ocala and Central Florida), a heater is what keeps a pool usable year-round instead of six months a year. The two main options are gas heaters and heat pumps, and the right pick depends less on brand and more on how you actually use your pool.
How each one works
A gas heater (propane or natural gas) burns fuel to heat water directly. It reaches target temperature fast, often in under an hour, regardless of outside air temperature. A heat pump instead pulls warmth from the surrounding air and transfers it into the pool, similar to how a refrigerator works in reverse. It's efficient, but it depends on the air being reasonably warm (generally above 50°F) to work well, and it heats more gradually.
Upfront cost vs. running cost
Gas heaters cost less to buy and install but more to run, since fuel is a continuous expense every time the heater fires. Heat pumps cost more upfront but use a fraction of the energy per degree of heating, so the running cost is much lower over a swim season. For a pool that gets heated occasionally, for a weekend or a holiday, a gas heater's lower upfront cost and fast heat-up time usually win out. For a pool that stays heated for weeks or months at a time, a heat pump's efficiency pays for the higher purchase price within a couple of seasons.
Sizing it correctly
Both heater types are sized in BTU output, and undersizing is the most common mistake. A heater that's too small for the pool's surface area and volume will run constantly and struggle to keep up on cooler days, especially with wind or an uncovered pool losing heat overnight. As a rough guide, a typical 15,000-20,000 gallon residential pool in Central Florida does well with a 250,000-400,000 BTU gas heater or an equivalent heat pump rated for the pool's surface area. A pool cover matters too. It cuts heat loss dramatically overnight and reduces how hard either heater has to work.
Shop these products
Thinking about a new pool instead?
If you're planning a new pool build rather than upgrading equipment on an existing one, our sister company Cool Pool of Florida builds custom fiberglass pools across Ocala, Orlando, West Palm Beach, and Port St. Lucie.
