Solar Pool Cover: How It Works and Which to Buy
A solar pool cover (also called a solar blanket) heats pool water by trapping solar energy and reducing heat loss overnight. In sunny climates, a solar cover can raise water temperature by 10-15°F and cut chemical evaporation by up to 70%. They cost $50-$400 for most residential pools, and most homeowners recover that cost within one season through reduced chemical consumption and lower heating bills.
Our complete beginner pool care guide covers where solar covers fit in your overall seasonal maintenance plan.
Is This Guide For You?
This guide is for you if:
- You want to extend your swimming season into spring and fall
- You’re looking to reduce heating costs or cut chemical consumption
- You’re deciding between cover types and want honest performance data
This guide is NOT for you if:
- You need a winter safety cover to close the pool. Solar covers and winter covers are different products. See our full pool winterizing guide for winter cover selection and installation.
- You already have a gas or heat pump heater and wonder if a solar cover still helps. It does, and the Pros section explains the economics.
How a Solar Pool Cover Works
Solar covers look like oversized bubble wrap, and the comparison is intentional. The mechanism relies on those bubbles:
- Bubble side faces down into the water. This is the most common installation mistake. The bubbles go in the water, smooth side up.
- The bubbles transmit sunlight into the pool and trap heat. Clear and light-blue bubble material allows sunlight to pass through and warm the water below. Think of it as a greenhouse for your pool surface.
- Reduces evaporative heat loss. This is where most of the value is. Research from the NREL solar pool heating study{:target=“_blank”} indicates that 60-75% of pool heat loss occurs at the water surface through evaporation. Blocking that surface dramatically slows heat escape.
- Acts as an insulating blanket at night. After sunset, the cover traps the day’s heat gain instead of letting it escape into cool air.
- Reduces chemical evaporation. Chlorine and pH adjusters evaporate along with water. A cover that cuts evaporation by 30-70% reduces how much you add each week. See reducing chemical evaporation for how this interacts with your water balance.
How Much Heat Does a Solar Cover Add?
The short answer: 10-15°F in sunny conditions, with meaningful variability by climate and pool size.
Here’s what the data shows:
- Average temperature increase: 10-15°F in direct sun. Overcast or heavily shaded pools see smaller gains, sometimes 4-8°F.
- Overnight retention: Reduces overnight temperature loss by 5-10°F. This matters most in spring and fall when nights are cool.
- Energy equivalent: On a 15,000-gallon pool, a solar cover provides heating equivalent to $50-$200 per month in gas or electric costs avoided. The DOE pool heating efficiency recommendations{:target=“_blank”} confirm solar covers as the most cost-effective pool heating supplement available.
- Chemical savings: Reduces water and chemical evaporation by 30-70%, which translates directly to lower weekly chlorine and pH adjuster costs.
- Season extension: Realistically, 4-8 weeks of additional swimming in most US climates. In the Southeast and Southwest, gains can be higher. In the Midwest and Northeast, expect the lower end of that range.
One honest caveat: solar covers do not replace a gas heater or heat pump in cold climates. They supplement heating. If your pool is 60°F in October in Minnesota, a solar cover gets you to 70°F, not 80°F.
Solar pool cover costs
| Size / Type | Price Range |
|---|---|
| Small (up to 12x24 ft) | $50-$150 |
| Medium (up to 18x36 ft) | $100-$250 |
| Large (24x40+ ft) | $200-$400 |
| Solar rings (alternative, per set) | $30-$80 |
| Reel system | $50-$250 |
A few cost factors worth noting:
- Solar blankets are sold oversized. You buy a rectangle and trim it to your pool’s actual shape. Most pool supply stores sell them in standard size rectangles; trimming to kidney or freeform shapes takes 20-30 minutes with scissors.
- Lifespan: 3-6 years. UV breaks down the plastic bubbles over time. They become brittle, crack, and lose their insulating effectiveness. Budget for replacement every 3-5 years.
- Total cost of ownership: A $150 cover that lasts 4 years costs $38/year. Factor in chemical and heating savings, and most solar covers pay for themselves in the first season.
For a monthly pool cost breakdown including where solar covers fit in your annual budget, that guide has the full numbers.
Types of solar pool covers
“Solar cover” is used loosely to describe three different products. Make sure you’re comparing the right thing:
| Type | How It Works | Cost | Pros | Cons |
|---|---|---|---|---|
| Solar blanket (sheet) | Single sheet covers entire pool surface | $50-$400 | Maximum coverage and effectiveness | Heavy/awkward to remove; needs a reel for practical use |
| Solar rings | Interlocking rings float on the water surface | $30-$80 per set | Easy to remove section by section; good for irregular shapes | Gaps between rings reduce heating effectiveness by roughly 20% |
| Liquid solar cover | Chemical additive that forms a thin film on the water surface | $20-$60/season | Zero handling required; just pour and forget | Less effective than physical covers; best for small above-ground pools |
We recommend solar blankets for most inground pools. Solar rings work better for above-ground pools or pools with unusual shapes where a blanket is difficult to trim and fit. Liquid solar covers are a viable supplement in a pinch, but not a replacement for a physical cover.
Choosing the right solar cover: thickness and color
Thickness:
- 8 mil: Lightest and cheapest. Degrades fastest in UV. Good for above-ground pools or buyers who prioritize cost over longevity.
- 12 mil: Standard choice. Balances durability and heat retention for most inground pool owners.
- 16 mil: Heaviest and longest-lasting. Best insulation. Worth the premium if you’re a year-round pool owner or have a heated pool where heat retention savings are maximized.
Color:
- Clear or light blue: Maximum light transmission into the water below. Best for heating. Most popular choice.
- Dark blue or black: Absorbs more solar energy directly into the cover material, but transmits less light into the water. Better in very cold climates where direct absorption is more valuable than light transmission.
- Blue/silver (dual-layer): The silver side reflects heat back into the water at night; the clear side heats during the day. Good all-around choice for pools where nighttime retention is a priority.
Do You Need a Solar Cover Reel?
Strongly recommended. Here’s why:
A solar cover on a standard inground pool weighs 30-60 lbs when wet. Rolling it up by hand, carrying it off the deck, and unrolling it again every time you swim is not something most pool owners sustain for more than a season.
Reel cost runs $50-$250 depending on material (plastic vs aluminum vs stainless). Deck-mounted reels add convenience; free-standing reels work fine for most setups.
If you end up with a reel and a winter cover too, managing both is easier than it sounds. For context on the full seasonal picture, see our full pool winterizing guide.
Pros and cons
Pros:
- Raises water temperature 10-15°F in sunny conditions
- Reduces chemical consumption by 30-70% through reduced evaporation
- Extends swimming season by 4-8 weeks in most US climates
- Reduces water evaporation (lower water bill, fewer refills)
- Pays for itself within one season in most climates through fuel and chemical savings
Cons:
- Must be removed before swimming (adds 5-10 minutes without a reel; under 2 minutes with one)
- Degrades in 3-6 years as UV breaks down the bubble material
- Does not replace a heater in cold climates
- Can trap algae against pool walls if left on a pool with chemistry imbalance
- Heavy and awkward to handle without a reel
Once you have a solar cover in rotation, you’ll notice your chemical usage drop within a few weeks. The EPA water efficiency in pools{:target=“_blank”} guidance recommends solar covers specifically as a tool for reducing both chemical and water consumption.
FAQ
Can I leave a solar pool cover on all the time?
No. Remove it whenever you swim. Beyond that, remove it for a few hours weekly to let any chlorine off-gassing from the water surface dissipate. Never add shock or liquid chlorine with the cover on, and don’t put the cover back on for at least 8 hours after shocking.
Do solar pool covers actually heat the pool?
Yes, with realistic expectations. In sunny conditions, 10-15°F of temperature gain is well-documented. Cloudy or heavily shaded pools see smaller gains. A solar cover is a heating supplement, not a heating system.
How long do solar pool covers last?
3-6 years depending on UV exposure, how carefully you handle the cover, and whether you store it properly between uses. Leaving a cover sitting on a sunny deck when not in use accelerates degradation significantly. Store it rolled on the reel or in a shaded area.
Which side of a solar cover goes down?
Bubble side down, smooth side up. The bubbles face into the water. This is the most common installation mistake. If your cover has been installed smooth-side-down, flip it. Heat retention and light transmission both depend on correct orientation.
Are solar pool covers worth it?
Yes, for most pool owners. At $100-$250 for a medium-sized cover, the investment pays for itself within one season for anyone who heats their pool or who’s dealing with high weekly chemical costs. The ROI is weakest for unheated pools in already-warm climates where the temperature difference is modest.
For removing water that accumulates on top of your cover during winter, see our guide on removing water from your pool cover for pump selection and usage.
For everything else about ongoing pool maintenance, the pool maintenance basics guide covers filter care, chemical balance, and seasonal tasks.