Pool Covers: Cutting Evaporation in Perth’s Heat 

Perth’s climate is one of the best things about owning a pool here – long, hot, dry summers mean a long swimming season. But that same heat (combined with low humidity and Perth’s notorious sea breeze) also means evaporation from an uncovered pool happens faster than many owners realise. Over a summer, that can add up to a genuinely significant amount of water.

A pool cover is one of the simplest, most effective ways to address this – and the right choice depends on how you use your pool.

IMPORTANT TIP: Please refer to your How to care for your Fibreglass Pool warranty booklet to make sure your pool blanket meets the warranty terms and conditions. Your blanket should be cut 20mm smaller than the pool’s perimeter. Remove it completely for at least one to two days each week so trapped gases can escape, and take it off over winter. This keeps your chlorine within 1.5–3.0ppm and your water at 29°C or below. Over-chlorination can damage your pool surface and equipment and void your warranty.

Why Evaporation Matters More in Perth

Evaporation rates increase with heat, low humidity, and wind – and Perth’s summer climate checks all three boxes. An uncovered pool can lose a noticeable amount of water depth over the warmer months purely through evaporation, separate from any water lost through splash-out or backwashing the filter. This matters for a few reasons:

Types of Pool Covers

Solar covers (bubble covers). These floating covers sit directly on the water’s surface and work primarily by reducing evaporation while also providing some solar heating benefit – the bubble design helps trap warmth. They’re a cost-effective entry point, though they need to be manually placed and removed for swimming.

Thermal covers. Similar concept to solar covers but often with additional insulating properties, helping retain heat overnight as well as reducing evaporation during the day.

In-ground pool blanket boxes with automatic pool covers. Undoubtably the most popular option for homeowners due to their seamless visual appeal around the pool area. An automatic cover rolls out from a recessed in-ground blanket box and retracts at the push of a button, or via your pool automation system, if you have one. Beyond evaporation and heat retention, automatic covers also add a safety barrier layer and help keep debris out of the pool – particularly useful if your backyard has trees nearby.

Liquid pool covers. A less visible option – these are additives that form an invisible molecular layer on the water’s surface, reducing evaporation without a physical cover that needs to be removed for swimming. They’re typically used alongside (not instead of) other water-saving measures, and need to be reapplied periodically.

Technician opening an in-ground pool blanket box to access the pool cover roller mechanism.

How Much Difference Does a Cover Actually Make?

The exact reduction depends on the cover type, how consistently it’s used, and your specific conditions (pool size, sun exposure, wind exposure) – but covering a pool when it’s not in use, particularly overnight and on hot, windy days, meaningfully reduces evaporation compared to leaving the surface exposed continuously. For pool owners focused on minimising both water use and during the cooler months, heating costs, consistent cover use is one of the most direct levers available.

Choosing the Right Cover for Your Pool

If you swim frequently and want minimal hassle - an automatic cover offers the best combination of convenience (no manual handling) and the added benefits of safety and debris reduction, though it’s a larger upfront investment.

 

If you’re working with a tighter budget - a solar or thermal cover provides meaningful evaporation reduction at a lower cost, with the trade-off being manual placement and removal.

 

If you want something low-profile – a liquid cover can be used without changing how the pool looks or how you access it, though it’s generally most effective as a complement to other measures rather than a standalone solution.

 

For pools near trees or in windy spots - an automatic cover’s debris-reduction benefit can be an added bonus on top of the water-saving function, reducing how often you need to skim or vacuum.

Venice Slimline 7.2m x 3.5m fibreglass pool with tropical landscaping and glass fencing

Other Water-Saving Habits Worth Combining With a Cover

Want advice on which cover type suits your pool and budget? Get in touch and we can talk through the options.

Frequently Asked Questions

Do pool covers really reduce evaporation significantly?
Yes – covering a pool, particularly overnight and during hot, windy periods, meaningfully reduces evaporation compared to leaving the surface exposed continuously. The exact amount depends on the cover type, pool size, and how consistently it’s used.
This depends on your priorities — automatic covers offer the most convenience and added safety/debris benefits, while solar and thermal covers offer a more affordable entry point with similar evaporation benefits when used consistently.
Yes – by reducing evaporation, covers also reduce the amount of warmed water lost to the air, meaning less work for your pool heater to maintain temperature.
Liquid covers can reduce evaporation without a physical cover, but they’re generally most effective as a complement to other water-saving measures rather than a complete standalone solution, and need periodic reapplication.
 It’s generally recommended to ‘air out’ your pool a minimum of every 3-4 days to release heat buildup and let the pool chemicals breathe so they can do their job effectively. Check your cover frequently and ensure it isn’t overlapping the pool as this traps additional heat which can create chlorine buildup in the pool.

Reducing evaporation through consistent cover use is one of the more direct ways pool owners can reduce their overall water use – relevant for anyone wanting to be mindful of water consumption, particularly during Perth’s hot summer months.

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We invite you to visit our display centres or contact us today for a free quote and site appraisal. Let Barrier Reef Pools WA and its skilled, experienced and friendly sales staff work with you in selecting the very best design to meet your special needs.

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