Pool Heater Cost Calculator (USA)
Estimate what it costs to heat your pool by heater type, see the daily, monthly and seasonal running cost plus the one-time heat-up cost, compare gas, propane, heat pump and electric side by side, and download a PDF report.
| Target | Water–Air | Per Day | Per Month | Per Season |
|---|---|---|---|---|
| Calculate to see scenarios | ||||
The highlighted row is your target temperature. Every degree warmer raises both heat loss and cost, and most heat escapes by evaporation — a cover is usually the biggest single saving.
How to Use the Pool Heater Cost Calculator
Find out what it costs to hold your pool at a comfortable temperature — per day, per month and per season — and what the first heat-up costs, in four steps.
Enter surface area and volume
Surface area drives the ongoing heat loss; volume drives the one-time heat-up. Length times width is close enough for a rectangle — both numbers are used differently.
Set your temperatures
Current water temperature, the target you want, and the average air temperature where you live. The gap between water and air is what you’re paying to maintain.
Choose the heater and your rate
Natural gas, propane, heat pump or electric. The efficiency field switches to COP for heat pumps and the price field to therms, gallons or kWh — put in the rate off your own bill.
Add cover, exposure and season
Say whether you use a solar cover, how exposed the pool is to wind, and how many days a year you heat. Then read the costs and download the two-page PDF.
What’s Included
Running cost and heat-up cost are two different numbers, and the heater that’s cheapest to buy is rarely the cheapest to run — this separates all of it.
Four heater types
Natural gas, propane, heat pump and electric resistance, each with its own energy unit and typical starting rate — and the efficiency field becomes COP when you pick a heat pump.
Daily, monthly, seasonal
The cost to hold your target temperature per day, across a 30-day month, and over the whole heating season — so you can see the number that actually lands on the bill.
One-time heat-up cost
Bringing cold water up to temperature is a separate, much larger charge than holding it there. That figure is called out on its own so opening week doesn’t come as a surprise.
Cover and wind exposure
Toggle a solar cover on or off and set the site as sheltered, average or windy — then see, in dollars per day, exactly what the cover is saving you or would save you.
Fuel comparison and charts
All four heater types priced on your pool side by side, plus a line showing cost accumulating across the season from the heat-up onward.
Temperature table and PDF
What every target from 76°F to 90°F would cost per day, month and season, with your setting highlighted — all of it in a branded two-page report.
By the Numbers
A quick snapshot of the physics and options working behind the estimate.
gas to heat pump
one gallon by 1°F
a cover can cut
sheltered to windy
no sign-up needed
Built for “What Will This Actually Cost Me Per Month?”
Heater brochures quote BTUs and COPs. Utility bills arrive in dollars. This is the bridge between the two.
Heater shoppers
Weighing a gas heater against a heat pump? Price them both on your own pool at your own rates — the gap in running cost is usually what decides it, not the sticker.
Season extenders
Wondering whether it’s worth heating through April and October. Set the air temperature for those months and see what the extra weeks of swimming really cost.
Owners with a bill shock
Already heating and startled by the gas bill. Try a lower target, a cover and a shorter season here first, and see which change moves the number most.
Heat Escapes From the Surface, Not the Deep End
Seven things that decide whether heating your pool is an affordable habit or a bill you dread.
- 1Surface area sets the running cost, not gallons. Heat leaves through the water’s surface, so a wide shallow pool loses more than a small deep one holding the same volume. Volume only matters for the initial heat-up, which is why the two figures are entered separately.
- 2A cover is the cheapest upgrade you’ll ever make. Most heat loss is evaporation off the surface, and a solar cover largely stops it — often cutting heating cost by more than half. Nothing else you can buy for the price of a cover comes close.
- 3Every degree costs, and the last few cost most. The bill tracks the gap between water and air, so going from 80°F to 84°F can add a noticeable share to a season. Try dropping the target a degree or two before you assume the heater is the problem.
- 4Wind matters more than people expect. Air moving across the surface accelerates evaporation, which is why an exposed pool costs meaningfully more than a sheltered one. A fence, hedge or well-placed planting is a permanent reduction in running cost.
- 5Heat pumps are cheap to run and slow to react. They move heat rather than making it, which makes them the least expensive option per degree — but they need reasonably mild air to work well and take far longer to bring a cold pool up. They suit holding a temperature, not rescuing a weekend.
- 6A bigger heater doesn’t cost more to run. Output rating changes how fast you get to temperature, not the energy needed to hold it — the same heat loss has to be replaced either way. Size for how quickly you want to heat, and for the fuel you can actually supply.
- 7Use the rate from your own bill. Published averages hide delivery charges, tiered pricing and seasonal rates, and propane in particular swings with the market. Take the effective cost per therm, gallon or kWh off a recent statement and the estimate becomes worth something.
Frequently Asked Questions
Answers to the most common questions about heating cost, heater types, covers and heat-up time.
How much does it cost to heat a swimming pool?
There’s no single figure, because the cost depends on how far above the air temperature you’re holding the water, how much surface area is losing heat, whether the pool is covered and what you pay for energy. A modest gap of a few degrees in mild weather is inexpensive; holding a large uncovered pool well above a cool autumn night is not. That’s why this calculator asks for your own dimensions, temperatures and rate rather than quoting an average — the range between the cheapest and most expensive realistic setups is enormous.
Which pool heater is cheapest to run?
A heat pump, in most climates and at most rates. It doesn’t create heat, it moves heat out of the outside air into the water, which is why it can deliver several units of heat for every unit of electricity it consumes. Natural gas usually comes next, propane is typically the most expensive fuel per unit of heat, and electric resistance heating is expensive because every kilowatt-hour becomes exactly one kilowatt-hour of heat. Switch between all four in the calculator and the comparison chart prices them on your pool at your rates.
Does a solar cover really save money?
Substantially, yes. Evaporation is the dominant way a heated pool loses heat — turning water to vapour carries away far more energy than radiation or conduction through the walls — and a floating cover stops most of it. Covers also add a little passive solar gain during the day. The catch is that it only works when it’s on, so a cover used a few nights a week delivers a fraction of the saving. Toggle the cover setting in the calculator and the per-day difference appears in the summary cards.
How long does it take to heat a pool?
Work out the energy first: raising one gallon by one degree takes about 8.34 BTU, so lifting 20,000 gallons by 10°F needs roughly 1.7 million BTU. Divide that by what your heater actually delivers per hour — a 400,000 BTU/hr gas heater running at 84% efficiency puts out around 336,000 — and you get something near five hours, before accounting for the heat escaping while you go. Gas and propane heaters do this in hours; a heat pump doing the same rise is usually measured in days, which is the real trade-off for its lower running cost.
What temperature should I set my pool to?
Most people find somewhere between 78°F and 82°F comfortable for general swimming, with lap swimmers often preferring the cooler end and small children, older swimmers and anyone just floating around preferring warmer. Since cost rises with every degree above the surrounding air, the practical approach is to start at the low end of comfortable and only raise it if people complain. The temperature table in the calculator shows what each step up would add per day, per month and across the season.
Is a heat pump worth it compared with gas?
It depends on how you swim and where you live. A heat pump costs more up front and heats slowly, but the running cost is low enough that it often pays back over a few seasons for someone holding a steady temperature all summer. Gas suits the opposite pattern — a pool used occasionally, heated quickly for a weekend, then left alone — and keeps working when the air turns cold, where a heat pump’s efficiency falls away. Compare the seasonal running cost of both here, then weigh it against the installed price difference from your local quotes.