Short answer: yes. A properly fitted solar bubble cover stops about 95% of the evaporation from your pool while it’s on. That figure isn’t from a cover manufacturer. It comes from an independent field study, and the real-world saving depends on one thing more than any other: how often the cover is actually on the pool.
Here’s what the research shows, what it means at home, and where the limits are.
What the research found
In 2015, Cal Poly’s National Pool Industry Research Center in California tested the main types of pool cover side by side. The pools were identical, with one left uncovered as a control. Water levels were measured every day for 65 days and corrected for leaks.
| Cover type | Evaporation reduction |
|---|---|
| Foam cover | 95.9% |
| Bubble (solar) cover | 94.9% |
| Solid track cover | 93.9% |
| Solar discs / rings (partial cover) | 50.1% |
| Liquid evaporation suppressant | 14–16% |
Source: Cal Poly / National Plasterers Council Evaporation Study.
Three things stand out:
- A bubble cover performs about as well as a solid cover. The top three were within about one percentage point of each other.
- Partial covers save about half. Discs and rings leave open water between them, and open water evaporates.
- Liquid “invisible covers” barely help. At around 15%, they’re not a real substitute for a physical cover.
The US Environmental Protection Agency’s WaterSense programme reaches the same conclusion: physical pool covers are the most effective way to cut evaporation, and solar covers achieve 50–95% depending on shape and how much of the surface they cover.
Why the saving at home is lower than 95%
In the study, the covers stayed on day and night. At home you take the cover off to swim, and sometimes you forget to put it back.
That’s why the US Department of Energy uses a more down-to-earth figure: covering a pool when it isn’t in use cuts the top-up water you need by 30–50%, and cuts heating costs by 50–70% for heated pools.
So the honest way to put it: the cover does its job almost perfectly while it’s on. How much you save depends on how much of the day it stays on. Uncovered hours on hot, windy afternoons cost you the most, so that’s when the cover matters most.
How a cover stops evaporation
Evaporation happens at the surface. Sun heats the water, dry air takes up the moisture, and wind carries it away and brings in drier air. A cover breaks all three by sitting on the water and sealing the surface off from the air. No open surface means almost nothing can evaporate.
This is also why a cover needs to fit properly. Gaps at the edges, or a cover cut too small, leave open water where evaporation carries on.
What else a cover saves
Water isn’t the only thing that leaves when a pool evaporates:
- Heat. Evaporation is the biggest source of heat loss from a pool. A solar bubble cover keeps that heat in and adds some of its own from the sun. Our Aqua-Dome is rated for up to 8°C gain and the Aqua-Bubble for up to 6°C.
- Chemicals. Less top-up water means less fresh water to rebalance. The US DOE puts the chemical saving at 35–60%.
- Cleaning time. A covered pool collects far less dust, leaves and debris.
One thing a solar cover won’t do
A solar bubble cover isn’t a safety cover. It floats on the water and will not hold the weight of a child or a pet. If you need to keep children out of the pool, you need a certified safety net or safety cover. See our safety nets and covers →
Which cover should you choose?
If your main goal is cutting evaporation, any full-coverage bubble cover that fits your pool properly will do the job. The real differences between our three solar covers are heat gain, warranty and price:
- Aqua-Dome: the most heat gain and the longest warranty, for heated pools and people who swim through more of the year.
- Aqua-Bubble: the same water-saving protection with slightly less heat gain. Our most popular cover.
- Enviro-Bubble: our value option, for owners whose main aim is stopping water loss.
Compare all three and get your price →
Want to know how much your own pool is losing? See the numbers for common pool sizes →
FAQ
Does a solar pool cover really stop evaporation?
Yes. In independent testing, bubble (solar) covers reduced evaporation by about 95% while they were on the pool. At home the overall saving depends on how many hours a day the cover stays on.
Is a bubble cover as good as a solid cover for saving water?
For evaporation, yes. In the Cal Poly study, bubble covers (94.9%) and solid track covers (93.9%) performed almost identically. The difference is safety: a solid safety cover can hold weight, but a bubble cover can’t.
Do solar rings or discs work?
Partly. Because they leave gaps of open water, solar discs cut evaporation by about half in testing, far less than a full cover.
Do liquid pool covers work?
Not well. Liquid evaporation suppressants cut evaporation by only about 15% in independent testing.
Should I leave the cover on all the time?
Keep it on whenever nobody is swimming, especially on hot, windy days and overnight. Those uncovered hours are where most of the water is lost.
Is a solar cover a safety cover?
No. Solar bubble covers float on the water and can’t support a person’s weight. Use a certified safety net or cover if you need to keep children out.
Sources: Cal Poly / NPC Evaporation Study — Pool & Spa News summary · US EPA WaterSense — Pools and Outdoor Water Features · US Department of Energy — Swimming Pool Covers