Solar cover vs pool heater
Not really a comparison — one stops loss and the other adds heat. But if you can only buy one, the arithmetic is clear.
Quick picks
In purchase order rather than by category, because the order is the actual answer to this question.
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | No photo Buy this first Sun2Solar 1200 Series Crystal Clear Solar Cover Attacks about 70% of your heat loss for about a hundred dollars. | Most pools, most budgets — the default recommendation | |
| 2 | No photo Buy this second, and smaller Hayward HeatPro Pool Heat Pump Sized to what is left after the cover, which is a cheaper heater. | Lowest running cost per degree when you want real temperature control | |
| 3 | No photo Buy this in between Blue Wave Solar Cover Reel The cover only pays if it goes on. This is what makes it go on. | Any inground pool with a cover you are not using enough |
#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 September 2, 2026.
They do different jobs
A heater adds heat. A cover stops you losing it. Framed as a comparison the question does not quite make sense — but people ask it because they have one budget, so here is the honest answer.
The measurement that decides it
Take your pool’s temperature at dusk and again at dawn, a foot down and away from the returns, on a still clear night. That difference is your overnight loss, and it tells you which half of the problem you actually have.
| 20,000 gal x 8.33 x 3°F | = 499,800 BTU |
| x 70% evaporation share (DOE) | = 349,860 BTU |
| x $10.75 per million BTU (heat pump) | = $3.76 a night |
| x $28.36 per million BTU (gas) | = $9.92 a night |
| x 150 nights | = $564.16 to $1,488.16 a season |
A hundred-dollar cover is defending several hundred to well over a thousand dollars of heat a year
And that is only the ceiling a cover can address — DOE's own published saving from covering a pool when not in use is 50 to 70% of heating cost, which is consistent with capturing most of it.
If your pool is dropping several degrees overnight, you are considering buying a heater to replace heat you could simply have kept. That is the whole argument, and it holds for almost every pool in a climate where anybody wants a heater.
Where a cover cannot help
Being fair to the heater, there are real situations a cover does not solve:
- Your pool has never been warm enough, even in midsummer. A cover keeps heat you collected. If you never collected enough, it has little to defend.
- You want the pool warm on a particular day, reliably. A cover cannot promise Saturday. A heater can.
- You want a genuinely long season — April to October in a cool climate. That needs added heat, not just retained heat.
- You will not use a cover. An honest self-assessment, and the reason a reel is on this page.
The right answer is both, in order
- Cover first. A hundred dollars, and it reduces the problem before you size the solution.
- Reel, if the pool is big enough to need one. Otherwise step one quietly stops happening.
- Re-measure the overnight drop. You now know your real remaining shortfall.
- Then size the heater to the gap that is left. That is a smaller, cheaper heater that runs less — and it stays cheaper every month for its whole life. How to size it.
Doing it the other way round means buying a bigger heater than you need and then running it against losses you could have prevented for a hundred dollars.
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 1200 Series Crystal Clear Solar Cover
The value pick, and the one whose logic actually holds up. A clear cover transmits more sunlight into the body of the pool instead of absorbing it at the surface, and 12 mil is the point where lifespan stops being the limiting factor. Bob Vila measured this and the 16-mil blue at the same 4 to 5 degrees in an hour, so you are paying less for the same measured result and giving up some years of service life.
Best for Most pools, most budgets — the default recommendation
| Thickness | 12 milThe manufacturer publishes no retrievable specification sheet; figure is as listed at retail. | Retail listing |
|---|---|---|
| Color | Clear | Retail listing |
| Stated lifespan | 3 to 4 years for the 12-mil clear tierSwim University's published figure for 12-mil clear covers generally. | Retail listing |
| Bubble side | Bubbles face 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
- Clear transmits more light into the water instead of stopping it at the surface
- 12 mil is the sweet spot: real service life without 16-mil bulk
- Cheaper than the 16-mil tier with no measured heating penalty
- Shorter published lifespan tier than 16 mil
- A clear cover shows algae and debris more obviously, which some people dislike
- Whether clear genuinely outlasts or under-lasts blue in the same thickness
- Real-world tear resistance at a pool with rough edges
- How much the clear material clouds over a season of UV
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 September 2, 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 September 2, 2026.
Blue Wave Solar Cover Reel
A reel is the single highest-leverage purchase in this whole category and almost nobody frames it that way. Every DOE saving figure assumes the cover is on the pool when the pool is not in use. A cover that takes two people and five minutes comes off on Friday and goes back on in October. A reel turns that into thirty seconds alone, which is the difference between the savings existing and not.
Best for Any inground pool with a cover you are not using enough
| Type | Wheeled above-ground-style reel for inground and above-ground useThe manufacturer publishes no retrievable specification sheet; figure is as listed at retail. | Retail listing |
|---|---|---|
| Why it matters | Converts a two-person five-minute job into a one-person thirty-second jobOur framing, not a manufacturer claim. The published savings all assume the cover is actually on. | Our arithmetic |
- Turns the cover into something you will genuinely use daily
- Keeps the cover off the ground, which is where covers get damaged
- Wheels, so it moves out of the way
- Costs a real fraction of what the cover itself costs
- Takes up deck space permanently
- Assembly is fiddly on every reel in this category
- How the tube and hardware hold up outdoors across seasons
- Whether the width range covers your pool without a wobble
- Assembly quality and hardware fit
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 September 2, 2026.
Questions people actually ask
Should I buy a solar cover or a pool heater?
Can a solar cover replace a pool heater?
Do I still need a cover if I have a heater?
- 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
Solar pool covers worth buying
Ranked on the specifications that actually differ between covers — thickness tier and published lifespan — because the only hands-on test in this category found no heating difference at all.
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.
How to heat a pool
The complete walkthrough: what your pool actually needs in BTU, every heating option priced per delivered million BTU, and the order to try them in.
Keeping a pool warm overnight
The specific problem of overnight heat loss: what causes it, what each fix is worth, and the order to try them in.
What size pool heater do I need?
How to size a heater from your pool's actual energy requirement, the input-versus-output rating trap, and why the answer gets smaller once you own a cover.