Solar cover savings calculator
One measurement you can take tonight, and this tells you whether a cover pays for itself and how fast.
Quick picks
What to buy once the arithmetic has told you it is worth buying.
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | No photo The cover to buy Sun2Solar 1200 Series Crystal Clear Solar Cover 12-mil clear, our overall pick. Roughly the price this calculator defaults to. | Most pools, most budgets — the default recommendation | |
| 2 | No photo If you want more seasons Sun2Solar 1600 Series Ultimate Blue Solar Cover 16 mil, 5-10 published years. Better cost per year, heavier to handle. | An inground pool you cover most nights, every season | |
| 3 | No photo Add it to the cost Blue Wave Solar Cover Reel An unused cover has an infinite payback. This is what stops that happening. | 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.
Will a solar cover pay for itself on your pool?
Read at dusk and again at dawn, a foot down, away from the returns. This is the only measurement this calculator needs.
Cheaper heat means a slower payback. It is still a payback.
Add the reel if you need one — an unused cover saves nothing.
DOE's 70% evaporation share is the ceiling; a real cover cannot catch all of it. 80% of that ceiling is a deliberately conservative default.
$7.94 a night · pays back in 17 nights
- Heat lost overnight
- 499,800 BTU
- Evaporation share (70%)
- 349,860 BTU
- Roughly what that is in water
- 40.1 gallons a night
- What the cover recovers
- 279,888 BTU
- Value per night
- $7.94
- Value per 30 nights
- $238.11
- Value per season (150 nights)
- $1,190.53
- Payback
- 17 nights of heating
| 20,000 gal x 8.33 x 3°F = 499,800 BTU | heat lost overnight |
| x 70% = 349,860 BTU | the evaporation share, per DOE |
| x 80% = 279,888 BTU | what a real cover catches |
| x $28.36 per million BTU = $7.94 | value of one night |
| $130.00 ÷ $7.94 = 17 nights | payback |
This counts heat only, which understates the case. DOE also publishes that a cover reduces make-up water by 30 to 50% and chemical consumption by 35 to 60%, and neither of those is in the numbers above. What the calculation cannot do is make you use the cover — an unused cover has an infinite payback, which is the real reason a reel belongs in the cost. Every constant is listed with its source on our methodology page.
Getting the measurement right
The calculator needs one number from you, and it is worth two minutes getting it properly rather than guessing.
- Read at dusk. A foot down, away from the return jets.
- Read at dawn, before the sun has been on the water. Same depth, same spot.
- The difference is your overnight loss.
Do it on a still, clear night if you can. That is the worst case and it is the one a cover helps most.
The calculation
| 1. gallons x 8.33 x your overnight drop | = heat lost overnight |
| 2. x 70% | = the evaporation share, per DOE |
| 3. x your capture rate | = what a real cover catches |
| 4. x cost per million BTU delivered | = value of one night |
| 5. cover cost ÷ nightly value | = payback in nights |
Step 3 is the honest one. DOE's 70% evaporation share is a ceiling — a cover cannot stop every gram, particularly at the edges — so the calculator defaults to catching 80% of that ceiling rather than all of it. Set it lower if you want to be pessimistic; the answer usually survives.
What this deliberately leaves out
The calculation counts heat and nothing else, which understates the case. DOE also publishes that a cover reduces:
- Make-up water by 30 to 50% — real money on a metered supply
- Chemical consumption by 35 to 60% — and chemicals are a recurring cost
Neither is in the numbers above. If your payback comes out marginal on heat alone, those two probably close it.
When the answer is no
Three honest cases where this arithmetic does not support buying a cover:
- An unheated pool. No heating bill, no heating saving. A cover still keeps the pool warmer and saves water and chemicals, but the payback calculation does not apply.
- A very short heating season. Four weeks a year on a heat pump may not clear the cost in year one. It will in year two.
- A cover you will not use. Payback is infinite, and this is much the commonest failure. Be honest with yourself, and if the answer is that the cover would not go on, buy a reel with it or look at rings instead.
For the worked version of this on a typical pool, with a sensitivity table across pool sizes and overnight drops, see the payback analysis.
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.
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
| 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 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
How do I measure my pool's overnight temperature drop?
Does a solar cover pay for itself?
Why does the calculator ask what percentage the cover catches?
- 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
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 fast a pool loses heat
Evaporation, radiation, convection and conduction, with the arithmetic on what each night actually costs and a measurement you can take yourself.
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.
Do solar pool covers work?
The 4-degrees-versus-15-degrees contradiction that runs through this entire category, reconciled from published physics. Three different quantities being reported as one.
Pool heater running cost calculator
Prices the same heating job across solar, heat pump, gas, propane and electric resistance simultaneously, with every energy price and efficiency editable.