Manufacturers promise spectacular savings, weeks of season gained, and water that’s always ready. Like any sales pitch, you have to know how to tell the promises from the observable results. Here’s what a solar cover really does, in concrete figures, and when the investment is justified.
A well-used solar cover reduces evaporation by up to 95%, raises the water temperature by 5 to 8 °C, extends the swimming season by two to four weeks in Quebec, and lowers chlorine consumption by 35 to 50%. For a standard in-ground pool, the return on investment is generally between one and two seasons.
Reducing evaporation: the most measurable benefit
Evaporation is invisible, but costly. An uncovered 50,000-litre residential in-ground pool loses between 1,500 and 4,000 litres per month during the summer season in Quebec, more during a heat wave (our article on leaks and evaporation details these figures).
Used at night and between swims, a solar cover:
- Reduces evaporation by 90 to 95%
- Saves on average 1,200 to 3,600 litres of water per month
- Limits the dilution of chemicals (which evaporate with the water)
- Stabilizes the water chemistry: more stable pH, longer-lasting chlorine
Over a four-month season, a family can save 5,000 to 14,000 litres of water, plus the equivalent amount of products that would have been needed to treat that volume.
Maintaining temperature: 5 to 8 °C more on average
The solar cover’s other big promise: retaining the heat captured during the day. According to Hydro-Québec, a solar cover can add between 5 and 8 °C compared with an uncovered pool, and reduce the energy consumption of an electric heater by 50% or more.
Concretely: water that capped out at 22 °C without a cover can reach 27-28 °C with one. For a pool in Quebec, this difference transforms the usable season. It’s also the main lever for avoiding having to turn on the heater in May and September.
Reducing the chemicals used
Three mechanisms explain the savings in products:
- Evaporated chlorine is preserved. Without a cover, chlorine dissipates into the air and under the effect of UV. With a solar cover, it stays in the water and keeps doing its job.
- UV no longer degrades stabilized chlorine. An opaque or tinted solar cover blocks some of the UV rays responsible for accelerated chlorine consumption.
- Less top-up water means fewer products to dose. Every addition of fresh water unbalances the chemistry and forces a new adjustment.
The total typically comes to 35 to 50% savings in chlorine and balancing products over an entire season.
Extending the swimming season
In Quebec, a pool without a cover is comfortable from mid-June to the end of August. With a solar cover used at night, the season stretches from late May to early October, that is, two to four weeks more at each end. For a family with children, these weeks often coincide with the start of school vacation and the back-to-school period, in other words, the weeks when the pool is used the most.
When to use it: only at night, or continuously?
The simple rule: the cover goes on as soon as no one is swimming, and comes off for swims.
| Period | Cover on? |
| At night, all season | Yes, always |
| During the day, outside of swims | Yes, except during a heat wave |
| During swims | No, never |
| Cool, cloudy days | On, to retain the accumulated heat |
Leaving the cover on the pool during a heat wave, in full sun, can overheat the cover and accelerate its deterioration. Some manufacturers recommend removing it during the hottest hours to extend its lifespan.
Limits and drawbacks to know about
A solar cover isn’t magic. Here are a few points to consider:
- Daily handling. Without a reel, putting on and removing the cover quickly becomes a chore for a large pool. A reel (manual or motorized) solves this problem but adds $300 to $1,500 to the budget.
- Limited lifespan. Most solar covers last 3 to 7 years depending on quality and exposure. Chlorine and UV eventually degrade the material.
- Appearance. Not everyone likes the look of a cover laid over the pool. Darker covers are less visible, but heat up more.
- Safety. A solar cover is not a safety cover. It doesn’t support the weight of a child or an animal. For safety, you need a dedicated cover or a motorized one.
- Maintenance. The cover must be rinsed regularly and kept away from concentrated chemicals (the shock zone).
Solar cover and home automation: the combination that changes everything
Motorized covers integrated into a home automation system deploy and retract from an app, or automatically according to programming. For a family that wants all the benefits without the chore, it’s the option that transforms the experience. Our article on home automation for pools details how these automations integrate.
“The solar cover is probably the most profitable investment we can recommend to a client. A small amount at purchase, a huge return on the water, the heating, the products, and the length of the season. When a client hesitates to put $10,000 toward heating, we often suggest they start with the cover: they recover 5 °C right away.”
– Tristan Dufour, owner and pool expert, Piscine Évolution
A pool that’s warmer, cleaner, simpler to manage. The solar cover isn’t a service that Piscine Évolution sells, but it’s an addition we recommend to almost all our clients. If you’re considering a broader modernization, such as a motorized cover, automation or integration into a home automation system to control it all from your phone, our team can guide you. Request an estimate for a modernization or automation, and get a plan suited to your pool and your usage.
