Is a pool heater worth it?
Sometimes. The answer depends on three numbers, and two of them are yours to measure before you spend anything.
Quick picks
One pick per answer. The cover is first because on most pools it changes whether the question needs asking at all.
| # | Product | Best for | Price |
|---|---|---|---|
| 1 |  Try this before deciding Sun2Solar 1600 Series Ultimate Blue Solar Cover For a lot of pools the heater is not worth it because the cover was. Measure the overnight drop first. | An inground pool you cover most nights, every season | |
| 2 |  Worth it if you hold a temperature Hayward HeatPro Pool Heat Pump About $10.75 per million BTU. The lowest-cost controllable heat, for pools used most days. | Lowest running cost per degree when you want real temperature control | |
| 3 |  Worth it if you heat on demand Raypak Digital Natural Gas Pool Heater Hours rather than a day. Pays off when you swim unpredictably and the running cost applies to few hours. | Heating fast and occasionally, rather than holding a temperature | |
| 4 | No photo Worth it if you have the roof SmartPool SunHeater S601P Solar Heating System Zero running cost forever, and no thermostat. The only heater whose payback is purely the purchase. | Adding real heat with no running cost, on a sunny site | |
| — | No photo Not worth it on a full-size pool An electric resistance pool heater About $53.75 per million BTU. The heater that makes the answer no. | Spas and very small above-ground pools only |
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked October 17, 2026.
The three numbers that decide it
“Is a pool heater worth it” is unanswerable as a general question and easy as a specific one. It comes down to three numbers, and the first two are yours:
- How many extra days you would actually swim. Not could. Would. A heater that turns a four-month season into six is worth far more than one that turns it into four and a half, and the honest answer for a lot of households is closer to the second.
- How much heat your pool loses overnight. A thermometer at dusk and at dawn. If the pool drops several degrees, a large part of what a heater would do is replace heat you could simply have kept, and the calculation changes completely.
- What it costs to put a million BTU into the water with the heater you are considering, which is the one number we can supply:
| Heater | Per million BTU | 20,000 gal, +10°F |
|---|---|---|
| Solar panels | $0.00 | $0.00 |
| Electric heat pump | $10.75 | $17.91 |
| Natural gas | $28.36 | $47.24 |
| Propane | $35.66 | $59.41 |
| Electric resistance | $53.75 | $89.55 |
EIA prices for June 2026 and the equipment assumptions we publish. Every step is shown here.
The arithmetic, done honestly
The mistake in most “worth it” answers is comparing the purchase price with the fun. The right comparison is the running cost per extra swimming day, and it is a short calculation. Take a 20,000-gallon pool in a shoulder month, losing about 3°F overnight and wanting it back each morning:
| 20,000 x 8.33 x 3°F | = 499,800 BTU a night |
| Heat pump: 0.4998 x $10.75 | = $5.37 a day |
| Natural gas: 0.4998 x $28.36 | = $14.17 a day |
| Electric resistance: 0.4998 x $53.75 | = $26.86 a day |
Roughly $5.37 to $26.86 per day, before the initial warm-up
A 3°F overnight drop is a typical uncovered figure on a still night; yours may be more or less, which is why the measurement comes first. Multiply by the days you would genuinely swim and you have a season's running cost to set against the purchase.
On a heat pump that is a few dollars a day to extend the season. On gas it is roughly double. On a resistance heater it is the kind of number that makes people stop using the thing they bought. Whether any of those is worth it is now a question about you, not about heaters — and that is the correct place for the question to end up.
When the answer is no
- Your pool drops several degrees overnight and has no cover. The Department of Energy attributes about 70% of a pool’s heat loss to evaporation and puts the saving from covering it at 50 to 70% of heating cost. A heater bought before a cover is a heater sized to replace heat you were throwing away. Cover first, then decide.
- You would swim a handful more days a year. The purchase and the install do not get cheaper per day when there are few days. Be honest about the number before you spend.
- The only heater you can install is electric resistance and the pool is full-size. At about $53.75 per million BTU the running cost ends the argument on 20,000 gallons. It remains sensible on a spa.
- The gas line cannot feed the heater and upsizing it costs more than the extra season is worth to you.
When the answer is yes
- You already cover the pool and it is still colder than you want. Your problem is heat supply, and a heater is the right purchase.
- You would use the pool most days for two or three more months. At heat-pump running costs, a few dollars a day for a swim most days is a purchase most households do not regret.
- You want the pool warm on particular days — visitors, weekends, a warm spell in April — and are willing to pay gas prices for a handful of hours to have it.
- You have unshaded roof and a long horizon. Solar panels cost nothing to run, so the payback is purely the install against the years you will keep the pool.
What it costs to own, not just to run
Purchase price is the number that gets compared and the least useful one. A heat pump costs more to buy than a gas heater of comparable real output and wins on total cost within a couple of seasons of steady use. A gas heater is cheaper to buy, dearer to run, and often carries a gas line upgrade that is not on the box. Solar panels have no running cost and an install that depends entirely on your roof. The lifetime cost page works all three through over ten years.
If, having done the measurement, the answer is yes, the ranked picks across every heater type are where to go next, and the running-cost calculator will put your own rates into every number on this page.
Every pick, in detail
What each one publishes, what is good and bad about it, and — the section this category usually omits — what we could not judge without owning one.
Sun2Solar 1600 Series Ultimate Blue Solar Cover
The cover to buy if you intend to keep using it in five years. 16 mil is the thickest tier the category sells, and thickness on a solar cover buys durability rather than heat — Bob Vila measured every cover in its hands-on group at the same 4 to 5 degrees, from 12-mil clear to 16-mil blue. Pay the extra for the one that survives being dragged over the coping twice a day, not for a temperature difference that did not show up in the only published one-hour test in this category.
Best for An inground pool you cover most nights, every season
| Price shown for | 24 ft roundThis product is sold in several sizes on one listing. The live price and photograph on this page are the ones Amazon returns for this variant; other sizes are priced separately. | Retail listing |
|---|---|---|
| Thickness | 16 milThe manufacturer publishes no retrievable specification sheet; figure is as listed at retail. | Retail listing |
| Color | Blue | Retail listing |
| Stated lifespan | 5 to 10 years for the 16-mil tierSwim University's published figure for 16-mil covers generally, not a Sun2Solar warranty statement. | Retail listing |
| Bubble side | Bubbles face the waterCategory-wide instruction, not brand-specific. The bubbles are the insulating layer and they have to touch the water. | Published standard |
4 to 5 degrees F in one hour
Claimed by Bob Vila, measured across all covers in their group. Conditions: One hour under 2pm sun on 89 to 92 degree F days. Source
Their figure was the same for every cover they put on the water. Read our reconciliation of what a one-hour reading actually measures before you plan around this number.
- Thickest tier sold, which is where the durability difference actually is
- Blue absorbs more of the incoming energy at the surface than clear does
- Cuts oversize to your pool shape with household scissors
- Heavy and awkward at 16 mil — a large inground cover is genuinely a two-person job without a reel
- Costs meaningfully more than the 12-mil version for no measured heating advantage
- Whether the seams hold up over five seasons of daily handling
- How the bubble layer survives repeated dragging over rough coping
- Whether the stated lifespan tier holds for this specific product line
These need a unit in hand across a season. We do not have one, so we do not have an opinion worth printing on them.
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked October 17, 2026.
Hayward HeatPro Pool Heat Pump
If you are heating a pool with electricity, this is the shape of machine to do it with. A heat pump moves heat instead of making it, and at the assumptions we publish it delivers a million BTU into the water for about a fifth of what an electric resistance heater costs to deliver the same. It is slower than gas and it fades as the air gets colder, which is exactly when you want it — that trade is the whole decision.
Best for Lowest running cost per degree when you want real temperature control
| Type | Air-source heat pumpThe manufacturer publishes no retrievable specification sheet; figure is as listed at retail. | Retail listing |
|---|---|---|
| Rating convention | Rated by BTU/hr OUTPUTThis is the trap in the category. Gas heaters are rated by fuel INPUT, heat pumps by heat OUTPUT. A 140,000 BTU heat pump and a 140,000 BTU gas heater do not deliver the same heat. | Published standard |
| Cost per million BTU delivered | About $10.75 at our published assumptionsUS average residential electricity at 18.34 cents/kWh (EIA, June 2026) and an assumed COP of 5.0. Both are substitutable on our running-cost calculator. | Our arithmetic |
- Cheapest running cost per delivered BTU of any controllable heater
- No gas line, no combustion, no flue
- Holds a set temperature rather than depending on the weather
- Slow — expect most of a day to move a full-size pool ten degrees
- Efficiency falls with air temperature, so it is weakest in the shoulder season
- High purchase price against a gas heater of comparable output
- The COP this specific unit achieves at your conditions
- Compressor and control-board longevity
- Noise at the distance your deck actually sits from it
These need a unit in hand across a season. We do not have one, so we do not have an opinion worth printing on them.
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked October 17, 2026.
Raypak Digital Natural Gas Pool Heater
The right answer when speed matters more than running cost — a weekend pool you want warm on Friday afternoon rather than one you hold at temperature all season. At the assumptions we publish, gas costs roughly two and a half times what a heat pump costs per delivered BTU, and it will get there in a fifth of the time. Buy the speed if you need the speed.
Best for Heating fast and occasionally, rather than holding a temperature
| Type | Natural gas or propane fired, digital controlThe manufacturer publishes no retrievable specification sheet; figure is as listed at retail. | Retail listing |
|---|---|---|
| Rating convention | Rated by BTU/hr INPUTA 400,000 BTU gas heater burns 400,000 BTU an hour and delivers roughly 82% of it. Do not compare that number directly against a heat pump's output rating. | Published standard |
| Cost per million BTU delivered | About $28.36 at our published assumptionsUS average residential natural gas at $24.09/Mcf (EIA, June 2026) and an assumed 82% thermal efficiency. | Our arithmetic |
- Fast — hours rather than most of a day on a full-size pool
- Works the same in cold air, unlike a heat pump
- Lower purchase price than a heat pump of equivalent real output
- Roughly two and a half times a heat pump's cost per delivered BTU
- Needs a gas line sized for it, which is often the real cost
- Propane instead of natural gas raises the running cost by about a quarter again
- The efficiency this specific unit achieves in service
- Heat exchanger life against your water chemistry
- Whether your existing gas supply can feed it without an upgrade
These need a unit in hand across a season. We do not have one, so we do not have an opinion worth printing on them.
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked October 17, 2026.
SmartPool SunHeater S601P Solar Heating System
Solar panels that plumb into the return line and heat the water with sunlight rather than fuel, which puts their running cost at zero — the only entry in the whole heating category where that is true. The trade is that you cannot dial in a temperature: the panels deliver what the sun gives them on the day, and on a cloudy week they deliver very little.
Best for Adding real heat with no running cost, on a sunny site
| Type | Roof, rack or ground-mounted solar collector panels, plumbed inline | Manufacturer |
|---|---|---|
| Collector area | Two 2 x 20 ft panels, 80 sq ft totalThis is the number to size from. The trade rule of thumb is collector area equal to 50-100% of the pool's surface, so a 16 x 32 pool needs several of these systems rather than one. | Manufacturer |
| Material | Polypropylene, stated not to corrode or scale | Manufacturer |
| Also required | One SK21 System Installation Kit per installation, sold separatelyThe manufacturer's own wording. One SK21 serves up to four of these two-panel systems. The panels on their own are not a complete installation, which is the commonest surprise in this product category. | Manufacturer |
| Running cost | $0 in fuelThe circulation pump is already running for filtration. There is no additional fuel or electricity cost attributable to the heat. | Our arithmetic |
Up to 6 to 10 degrees F
Claimed by SunHeater, on its own product page for the S601P. Conditions: Stated as under favorable conditions; no time period given. Source
Worth reading beside the figure below. The manufacturer's own claim for this product is 6 to 10 degrees. The retail listings for the same model say up to 15. The larger number is the one further from the manufacturer.
As much as 15 degrees F
Claimed by Bob Vila, describing the S601P. Conditions: Stated as requiring ample sunlight; no time period given. Source
Note the phrasing: with ample sunlight it can boost temperature by as much as 15 degrees. That is a cumulative ceiling reached over days of good sun, not a figure you will see in an afternoon.
- Zero fuel cost, forever — nothing else in this category can say that
- No combustion, no gas line, no additional electrical service
- Panels can be added to as the budget allows
- You get the sun's schedule, not yours
- Needs real unshaded mounting area, and plumbing work to install
- Does nothing on a cold cloudy week, which is when you most want it
- Actual heat output at your latitude, roof pitch and shading
- How the panel material survives a decade of UV and freeze cycles
- Whether the included fittings suit your existing plumbing
These need a unit in hand across a season. We do not have one, so we do not have an opinion worth printing on them.
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked October 17, 2026.
An electric resistance pool heater
Skip it for a full-size pool, and the arithmetic is not close. At the same electricity price, a resistance heater costs about five times what a heat pump costs to deliver the same heat, because it makes heat instead of moving it. It has a legitimate niche on a small above-ground pool or a spa where the volume is tiny and the install is a plug. On 20,000 gallons it is the most expensive way to heat water that exists.
Best for Spas and very small above-ground pools only
| Cost per million BTU delivered | About $53.75 at our published assumptionsUS average residential electricity at 18.34 cents/kWh (EIA, June 2026) at a coefficient of performance of 1.0. Compare with about $10.75 for a heat pump on the same electricity. | Our arithmetic |
|---|---|---|
| Efficiency | About 1:1 — no efficiency to argue about | Published standard |
- Cheap to buy and often just plugs in
- Genuinely sensible on a spa or a very small pool
- About five times a heat pump's running cost for identical heat
- Draws serious current, which frequently means an electrical upgrade
- On a full-size pool the running cost is punishing
- Element life in your water chemistry
- Whether your existing circuit can carry it
These need a unit in hand across a season. We do not have one, so we do not have an opinion worth printing on them.
#ad We earn a commission if you buy through this link, at no extra cost to you. It never changes the ranking. How this site is funded. Prices last checked October 17, 2026.
Questions people actually ask
Is a pool heater worth the money?
Is a pool heat pump worth it?
Is a solar cover enough instead of a heater?
How much does it cost to run a pool heater per month?
- Average retail price of electricity to US residential customers: 18.34 cents/kWh, June 2026U.S. Energy Information Administration · read 2026-09-02
- US residential natural gas price: $24.09 per thousand cubic feet, June 2026U.S. Energy Information Administration · read 2026-09-02
- US residential propane price: $2.674 per gallon, week ending 30 March 2026U.S. Energy Information Administration · read 2026-09-02
- Energy content conversion factors: 3,412 BTU per kWh, 1,036 BTU per cubic foot of natural gas, 91,452 BTU per gallon of propaneU.S. Energy Information Administration · read 2026-09-02
- U.S. Department of Energy pool-energy figures (evaporation share, BTU per pound evaporated, cover savings, recommended temperatures, wind effect)Recreonics, reproducing and attributing the U.S. Department of Energy · read 2026-09-02
- Pool heater roundup: the 8.33 BTU per gallon per °F figure, attributed on the page to Alicia Toedter of Leslie'sBob Vila · read 2026-09-02
Every URL above was fetched and returned content on the date shown. Where a figure is ours rather than somebody else’s, the arithmetic is on the page and on the methodology page. If you find an error in it, we would genuinely like to know.
Read next
Replacing a pool heater
What carries over from the old heater and what does not, why matching the old BTU is usually wrong, and why a replacement is the one affordable moment to switch fuel.
How long do pool heaters last?
Lifespan by heater type, the components that actually fail, what the warranties really cover, and how that should change what you buy in the first place.
What a pool heater really costs
Purchase, install and running cost taken together, and why the cheapest heater to buy is regularly the most expensive one to own.
How much does it cost to heat a pool?
The complete cost model: what a million BTU costs to deliver with each fuel, what that means per degree and per pool size, and why heat-up cost is not your monthly bill.
Solar cover vs pool heater
A hundred-dollar cover against a three-thousand-dollar heater, and the measurement that tells you which half of the problem you actually have.
Which pool heater to buy
Every type of pool heater ranked on what it costs to deliver a million BTU into the water, how many hours it needs to do it, and what the install actually involves.
Does a solar cover pay for itself?
The full payback derivation from one measurement you can take tonight, plus a sensitivity table for people whose pool is nothing like the example.