General information, not legal, engineering or insurance advice.
Most Florida homeowners who heat a pool choose between three options: an electric heat pump, a gas heater(natural gas or propane), or solar pool heating. A Florida Department of Community Affairs and University of Florida IFAS Extension fact sheet puts it simply: each option "has its own advantages and disadvantages."1 Here's how each one works and what to weigh.
How a pool heat pump works
A heat pump doesn't burn fuel. It uses electricity to capture heat and move it from one place to another, in this case from the outdoor air into your pool water. It does not generate heat itself.1
- Running cost: heat pump pool heaters generally cost more to buy than gas heaters, but they typically have much lower annual operating costs because they are more efficient.1
- Air temperature matters: because a heat pump draws its heat from the air, it works best when the air is warm. The U.S. Department of Energy notes that air-source heat pumps "with warm outside air are especially efficient."2On cold nights it delivers less heat, so it may take longer to bring the pool up to temperature after a cold front.
- Lifespan: with proper maintenance, heat pump pool heaters typically last longer than gas pool heaters.1
How a gas pool heater works
Gas pool heaters burn natural gas or propane (LP gas) to heat the water directly.1 Their strengths are speed and independence from the weather:
- A gas heater is most efficient when heating a pool for short periods and is ideal for heating a pool quickly.1
- That makes gas a good choice for pools that are not used on a regular basis.1
- Unlike heat pumps and solar, gas heaters can hold any desired temperature regardless of the weather.1
The trade-off is fuel. Running cost depends on your natural gas or propane price and how much you heat. If you don't have natural gas service, a propane tank and delivery are part of the picture.
How solar pool heating works
A solar pool heating system pumps pool water through solar collectors, usually on the roof, and returns it warmer. In pool systems, the swimming pool itself is the storage, and the pool's filtration pump circulates the water through the collectors. Unglazed polymer (plastic) collectors are typical for pool heating.3
- Operating cost: the Department of Energy describes solar pool heaters as cost competitive with gas and heat pump heaters, with a low annual operating cost.2 The Florida fact sheet calls solar pool heating "the most cost-effective use of solar energy in Florida."1
- Lifespan: solar systems typically last longer than gas and heat pump pool heaters.1
- Site: you usually need an unshaded area facing south, southeast or southwest, such as a roof.3Output depends on sunshine, so cloudy, cool spells mean less heat.
- Backup: most people don't use a backup heater with solar pool heating. Spas are the exception: owners may heat both pool and spa with solar but use a backup heater to get the spa hotter.3
Side-by-side
| Heat pump | Gas | Solar | |
|---|---|---|---|
| Heat-up speed | Slower; depends on air temperature | Fast | Depends on sunshine |
| Holds temperature in any weather | No | Yes | No |
| Purchase cost | Generally more than gas | Generally less than a heat pump | Get quotes |
| Operating cost | Typically much lower than gas | Depends on gas or propane price | Low |
| Lifespan | Typically longer than gas | Typically shortest of the three | Typically longest |
| Best fit | Pools used often through the season | Occasional use, fast heat, spas | Sunny roof, lower running cost |
Based on the comparisons in sources 1–3. Actual costs depend on your equipment, rates and how you use the pool.
What drives operating cost
Whatever you choose, a few things have a big effect on how much heating costs:
- A pool cover. Evaporation is by far the largest source of a pool's energy loss, and pool covers can save 50% to 70% of pool heating costs.2 The Florida fact sheet calls covering a pool when it's not in use the single most effective way to cut heating costs.1
- Your set temperature. The Department of Energy points to keeping pool temperatures at the lower end of the recommended range (78°F to 82°F) as a way to manage energy costs.2
- Energy prices. Your electricity rate (heat pump) or natural gas or propane price (gas heater).
- Wind, shade and season length. A windy, shaded pool loses heat faster, and heating longer into the cooler months costs more.
Questions to ask before you choose
- Which type do you recommend for how often I use the pool, and why?
- How did you size it? Please show the calculation (see our sizing guide).
- Does my electrical panel, gas supply or pump need upgrades, and is that in the quote?
- Who pulls the permit, and are electrical or gas permits needed?
- What do the manufacturer warranty and your labor warranty cover, and for how long?
- Are you licensed for this work? Check the number on the DBPR lookup.
Sources
- Florida Department of Community Affairs, Building A Safer Florida and University of Florida IFAS Extension, “Residential Swimming Pool Efficiency” fact sheet (May 2006).
- U.S. Department of Energy, Better Buildings, “Pool Efficiency” fact sheet.
- U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, “A Consumer’s Guide: Heat Your Water with the Sun” (DOE/GO-102003-1824, December 2003).