A solar cover and a heat pump solve the same goal — keeping pool water warm — through completely different means. A solar cover primarily reduces heat loss; a heat pump actively generates heat. This difference in approach also determines when each investment pays off and how the two can be combined.
How a solar cover works
A floating bubble cover on the surface serves two functions: it reduces evaporation (the main source of heat loss for an outdoor pool) and lets some sunlight through, mildly warming the water via a greenhouse effect. The investment is low, but the effect is limited to sunny days, and a pool without a cover overnight cools down about as fast as it would without one at all during the day too.
How a heat pump works
It actively draws heat from the air (or, more rarely, another source) and transfers it to the water, independent of weather and time of day, as long as the outdoor temperature is within the unit’s operating range. The investment is significantly higher, but the effect is predictable and controllable — the pool reaches the target temperature even in overcast weather.
Rough comparison of cost impact
| Parameter | Solar cover | Heat pump |
|---|---|---|
| Purchase price | low | high |
| Running costs | none (just the work of putting it on/off) | electricity consumption |
| Effect on evaporation heat loss | significant | doesn’t address it directly, but compensates via output |
| Active heating | no, just a mild greenhouse effect | yes, controllable to a target temperature |
| Weather dependence | high | low |
The cheapest combination in practice
The most effective and simultaneously cheapest approach is combining both: a solar cover reduces heat loss overnight and when the pool isn’t in use, so the heat pump doesn’t need to compensate for the entire loss and can run at lower output or for shorter periods to maintain the same temperature. In practice, this means noticeably lower heat pump electricity consumption compared with running without a cover.
FAQ
Is a heat pump worth it without a solar cover?
Yes, it works on its own, but without limiting evaporation it will have to compensate for higher heat loss, meaning higher electricity consumption for the same result.
Can a solar cover heat a pool sufficiently on its own?
For smaller pools and in warmer months, yes, noticeably. For larger volumes or in cooler periods, the effect is more supplementary than a main heat source.
Does a solar cover always need to be put on manually every night?
Without a reel it does; with a motorised or manual reel system, handling becomes much easier and the cover is far more likely to actually be used regularly.
Solar covers and heat pumps are both in the pool technology category. More articles on heating and savings are in the Guides section.
