Do you need a pool blanket with solar or a heat pump?

Quick answer: Yes. A pool blanket is the single cheapest way to make any pool heater work better. Evaporation is the biggest source of heat loss from an outdoor pool, and a cover used whenever the pool isn't in use can cut heating costs by 50 to 70 percent. Bubble (solar) blankets let most of the sun's warmth through. Thermal foam blankets hold heat better overnight. Both work with solar and heat pumps.

We'll be honest. If you're about to spend thousands on pool heating and you don't own a pool cover, buy the cover too. It's the difference between a heater that holds 28°C comfortably and one that works all night just to stand still.

Why a heated pool loses heat so fast

An outdoor pool loses most of its heat from the surface. Water evaporates, and every litre that evaporates carries a large amount of heat away with it. Evaporation is the biggest single source of heat loss, with most of the rest radiating off to the night sky. A well-fitted cover can stop up to 97 percent of evaporation, according to this Australian council fact sheet on pool covers, which also puts the saving on heating energy at 50 to 70 percent.

Adelaide makes it worse. Warm, dry, windy afternoons are perfect conditions for evaporation. So is a clear, cool night after a hot day. A cover stops most of that at the source, and it shortens the first warm-up in spring too (we worked through the numbers in how long it takes to heat a pool).

Pool blanket types compared

Cover type	How it works	Holds heat overnight	Adds heat from the sun	Handling	Best for
Bubble (solar) blanket	Air bubbles trap heat and let sunlight through	Good	Lets most sunlight through	Light, easy on a roller	Most heated pools, solar systems, budget
Thermal foam blanket	Closed-cell foam insulates the surface	Best	Blocks more sunlight	Heavier, needs a roller	Heat pump pools, year-round swimming, windy sites
Solar rings or liquid covers	Float or spread a thin layer on the surface	Fair	Some (rings)	No roller needed	Awkward pool shapes, stop-gap
Safety or hard cover	Solid barrier over the whole pool	Good	No	Motorised or manual track	Safety and debris first, heat second

For most Adelaide families with a heated pool, a good-quality bubble blanket on a roller is the sweet spot. If you're heating with a heat pump and want to swim into autumn or year-round, a thermal blanket earns its extra weight.

Using a blanket with solar pool heating

People sometimes worry a cover will stop their solar pool heating from working. It won't. The collectors on your roof heat the water as it's pumped through, and the warm water returns under the blanket. The cover just stops that heat escaping.

A clear bubble blanket still lets most of the sun's warmth into the water, and in Adelaide's dry, windy weather the evaporation it stops is worth far more than the sunlight it blocks. The simple rule: cover the pool whenever nobody's swimming, especially overnight.

A cover also means you can often get by with less collector area on the roof. That matters if your roof space is tight. Our solar sizing calculator gives you a starting point either way, and our DIY solar pool heating kits are listed by collector area, so you can see what a smaller system costs.

Using a blanket with a heat pump

With a pool heat pump, the cover's job is to protect the heat you've paid for. The heat pump holds your set temperature, and every degree the pool doesn't lose overnight is a degree it doesn't have to put back in the morning.

That's why we suggest a thermal cover for anyone running a heat pump year-round, usually paired with a larger unit or one from the Guardian Lux V range. You can compare every model and price in our pool heat pump range. Our running cost guide of $30 to $80 a week in season assumes a covered pool, and so do the answers on our pool heating FAQs page. Uncovered, the same heat pump can cost far more to hold the same temperature, and in cold snaps it may not keep up at all.

Five blanket mistakes to avoid

1. Leaving it off overnight. Nights are when the most heat escapes. Cover up after the last swim.

2. Buying it too small. Gaps at the edges leak heat. Get it cut to your pool's exact shape.

3. Bubbles facing up. On a bubble blanket, the bubbles go down, against the water.

4. Dragging it across pavers. It shreds the edges. A roller makes it a 30-second job and doubles as storage.

5. Leaving it baking on the pavers. Direct summer sun off the water breaks the plastic down quickly. Roll it up in shade.

What to do next

• Measure your pool surface, including steps and ledges, before ordering a cover.

• Pick your type from the table above based on how you heat and when you swim.

• Add a roller. It's what makes people actually use their cover every day.

• Ask us when we're quoting your heating. We'll factor your cover into the sizing, which can bring the price of the system down.

Ready to make your pool heating go further?

Heating already or still deciding? Either way, we'll look at your pool, your roof and your power and recommend the right system and cover together. Free onsite consultations across metro Adelaide. Call (08) 8349 4333.

Frequently asked questions

Does a pool blanket really keep the heat in?

Yes. Evaporation causes most of an outdoor pool's heat loss, and a cover stops most evaporation. Covering the pool whenever it isn't in use can cut heating costs by 50 to 70 percent.

Should I use a pool blanket with solar pool heating?

Yes. Solar collectors heat the water as it circulates, and the blanket keeps that heat in. A clear bubble blanket still lets most of the sun's warmth into the water. Cover the pool whenever nobody is swimming, especially overnight.

Bubble blanket or thermal blanket, which is better?

Bubble blankets are lighter, cheaper and let most of the sun's warmth through, which suits most heated pools. Thermal foam blankets insulate better overnight and suit heat pump pools used into autumn or year-round.

Which way up does a solar pool blanket go?

Bubbles down, touching the water. The flat side faces the sky.

How long does a pool blanket last in Adelaide?

It depends on the material and how it's stored. Covers kept rolled up in shade when off the pool last noticeably longer than ones left out in full summer sun.