Florida Pool Heating Cost Calculator

The calculator needs your pool's surface area and, optionally, your own energy prices. Surface area matters because a pool loses most of its heat from the surface, so the heating load follows square feet rather than gallons. For a rectangular pool, multiply length by width; a 15 by 30 foot pool is 450 square feet. For an oval, length times width times 0.785 is a good estimate. For a freeform pool, estimate the real water area rather than multiplying the longest length by the widest width, which overstates it. You can type the surface area in directly or enter length and width, and a switch tells the calculator whether the pool is covered when it isn't in use.

If you leave the prices alone, the calculator uses the same EIA figures as our cost guide: 15.36 cents per kWh for Florida residential electricity (year-to-date through June 2026), $2.46 a therm for Florida residential natural gas (EIA's 2025 average of $25.48 per thousand cubic feet, divided by 10.36 therms), and $3.572 a gallon for East Coast residential propane (March 2026). It also assumes a heat pump COP of 5.0, DOE's average, and a gas heater thermal efficiency of 84%; both can be changed. Swap in your own rates and equipment and the results update. The next section shows where to find the prices on your bills.

The output has two parts. The first is the cost of one million BTU of pool heat on each fuel, which puts every option on the same footing; a million BTU is roughly what it takes to raise a 15,000 gallon pool by 8°F. The second is an annual and average monthly estimate for holding the pool at 80°F every day of the year, uncovered or, with the cover switch on, covered, scaled from DOE's Miami tables. Solar appears in that annual table as the pump electricity it uses, because it has no fuel cost: about $111 a year, or about $9 a month, at the default electric rate.

Electricity: your bill lists the kilowatt-hours you used and the charges that go with them. Dividing the total bill by the kWh gives an all-in average, which slightly overstates the cost of extra kWh because it spreads the fixed monthly customer charge across your usage. The per-kWh charges alone (energy, fuel and any per-kWh riders and taxes) give a closer figure for what a heat pump adds. If your utility charges a higher rate above a monthly usage threshold, use the higher rate, because pool heating is likely what pushes you over it.

Natural gas: gas bills are in therms. Add up the per-therm charges, typically a gas supply or commodity charge and a delivery or distribution charge, and leave out the fixed monthly customer charge. The calculator asks for a price per therm. If your bill is in thousand cubic feet instead, divide that price by 10.36, since a thousand cubic feet of natural gas carries about 10.36 therms. Florida's $25.48 average works out to about $2.46 a therm.

Propane: use the delivered price per gallon on your last delivery ticket, without any annual tank rental, which you pay whether or not you heat. Propane is a retail price that varies by supplier and contract, so your own number beats any average.

Pump power, for solar: the calculator assumes a 1 kW pump running two extra hours a day. Your pump's label lists its watts, or its amps and volts (watts are roughly amps times volts), and many variable-speed pumps display their wattage. If yours draws more or less than 1,000 watts at the speed it runs for solar, scale the solar figure by the same ratio.

Every figure comes from one idea: heat needed, divided by the heater's efficiency, times the price of the energy. EIA's conversion factors do the rest: 1 kWh is 3,412 BTU, a cubic foot of natural gas is 1,036 BTU, a therm is 100,000 BTU, and a gallon of propane is 91,452 BTU.

Heat pump: one million BTU is 293.1 kWh (1,000,000 divided by 3,412). A heat pump at COP 5 delivers that heat using 58.6 kWh, and 58.6 kWh at 15.36 cents is $9.00. Gas: an 84% efficient heater needs 1.19 million BTU of gas to deliver one million (1,000,000 divided by 0.84). That's 11.9 therms of natural gas (10 therms divided by 0.84), $29.29 at the default $2.46 a therm ($29.28 if you work from EIA's unrounded $25.48 per thousand cubic feet), or 13.02 gallons of propane, $46.50 at $3.572. Electric resistance: 293.1 kWh with no multiplier, $45.02. Solar: two extra hours a day of a 1 kW pump is about 60 kWh a month, $9.22.

For the annual figure, the calculator starts from DOE's tables for a 1,000 square foot pool in Miami held at 80°F year-round. The heat pump table, which assumes an average COP of 5.0 and electricity at 13.01 cents, lists $1,989 a year uncovered and $409 covered. The gas table, which assumes an 80% efficient heater and gas at $1.09 a therm, lists $3,880 uncovered and $796 covered. Each figure is multiplied by your pool area divided by 1,000, then by your price divided by DOE's price, then by DOE's equipment assumption divided by yours (5.0 divided by your COP for the heat pump, 80 divided by your heater's efficiency for gas). For propane, the gallon price is first converted to a per-therm equivalent by dividing by 0.91452, because a gallon of propane holds 0.91452 therms.

Here is the annual method worked for a 15 by 30 foot pool (450 square feet) at the default prices. Heat pump, uncovered: $1,989 times 0.45 times 15.36 divided by 13.01 is about $1,057 a year, about $88 a month averaged over the year. Covered: $409 times the same factors is about $217 a year, about $18 a month.

Natural gas, uncovered: $3,880 times 0.45 times 2.46 divided by 1.09, times 80 divided by 84 for an 84% efficient heater, is about $3,753 a year, about $313 a month. Covered: about $770 a year, about $64 a month. Propane at $3.572 a gallon is about $3.91 per therm-equivalent, which makes it about 1.59 times the natural gas figure: roughly $5,959 a year uncovered and $1,222 covered.

The ratio is the reliable part. On Florida's average prices, the annual natural gas figure comes out at roughly three and a half times the heat pump figure, and propane at about five and a half times; per million BTU the gap is a little smaller, about three and a quarter and five times, because DOE's heat pump and gas tables aren't perfectly parallel. The cover changes every number by a similar factor, which is why it's worth more than any equipment upgrade.

The calculator is a sound starting point and an imperfect forecast. These are the places where your real bill will differ, roughly in order of how much they matter.

On running cost the order is clear at Florida's average prices. Solar can be one of Florida's lowest-operating-cost methods for heating a pool when the home has suitable roof orientation and sun exposure, because it uses only pump electricity. A heat pump is one of the lowest-cost powered methods, at about $9 per million BTU. Natural gas costs about three times as much per unit of heat, and propane about five times as much.

Installed cost runs on different drivers for each: collector area and the roof for solar, the electrical circuit and pad for a heat pump, and the gas supply and line sizing for gas. Our cost articles for each method explain those drivers and show what our recent priced jobs included.

Speed is the other half of the decision. Gas heats quickly and on demand. Heat pumps warm a swimming pool gradually over many hours. Actual heating speed depends on pool volume, heater output, starting water temperature, outdoor air temperature, humidity, wind conditions and whether the pool is covered. Proper heater sizing and the use of a pool cover can significantly affect recovery time. Solar adds heat whenever the sun is out and can't be called on during a cloudy cold snap, which is why it's often paired with a heat pump.

Use the calculator to rank your options, not to predict your bill to the dollar. If the ranking holds with your own rates, and on Florida prices it usually does, the decision comes down to how you use the pool. Owners who keep the pool warm all winter tend to save the most with a heat pump, solar or both. Owners who want an attached spa hot quickly, or heat only for weekends and guests, often find gas worth its running cost.

When you're ready for real numbers on equipment and installation, our cost articles for heat pumps, solar and gas heaters explain what moves the installed price, and our cost guide shows the full working behind every figure on this page. If your pool is in Sarasota, Manatee, Charlotte & Pinellas County, call (941) 323-6559 and we'll run these numbers against your actual pool, cover, enclosure and utility rates.