The short answer
What actually decides the cost of solar pool heating
Solar pool heating is sold as free heat from the sun, and it is the cheapest pool heating to run by a wide margin. But "free" is misleading. The collectors cost a few thousand dollars upfront, and the system still needs a pump running for hours a day through the swim season. The number that decides whether it is nearly free or a quiet drain on your bill is not the collectors, it is that pump, and where its electricity comes from. This page explains how solar pool heating is really priced, how to size it, and the one move that makes the running cost close to nothing.
Here is the core takeaway in one line: solar pool heating is the cheapest pool heating to run, but the cost that is left is the pump, not the collectors, and the timing of the swim season, not the brand of mat. The collectors are black tubes or mats on your roof that the sun heats for nothing. The only running cost is the electricity to pump your pool water up through them, and at a usage rate near 30 c/kWh that pump bill is real. The single biggest lever is to run that pump in the middle of the day on your own rooftop solar, where the power you use is worth only about 5 c as a forgone export rather than 30 c off the grid. The right question is not "which collector?" but "how do I size it correctly and run the pump on free midday power?"
Reframe the assumption: most buyers optimise the wrong variable. They shop collector brands and try to save on collector area, then run the pump for extra hours to make up the heat. That quietly converts "free" solar warmth into a meaningful electricity bill. Size the collectors to your pool, run the pump on midday solar, and add a cover, and the running cost is close to nothing.
Interactive explainer
Size your collectors and see the real running cost
Set your pool size and how you run the pump. We show the collector area you need, and what the pump costs to run across the season on grid power versus on your own midday solar.
Your pool and pump
Move the sliders below. Everything updates live. Nothing is stored.
Saving from running the pump on midday solar
$/season
Illustrative only. Collector area is your pool area times the coverage you set, following the 80 to 100% rule. Pump energy is pump kW times hours per day times season days. Grid power is valued at 30 c/kWh; midday solar at the 5 c export you forgo by self-consuming. It assumes you have rooftop solar and can shift pump hours to the middle of the day. Real results depend on your pool, climate, tariff and solar system. Sources: AER DMO 2025-26, typical Australian retail rates.
The blind spot
Why most solar pool heating guides set you up to overspend
Most articles about solar pool heating do three unhelpful things, and each one quietly costs owners money.
First, they call it free heat and stop there. The sun is free, but the pump is not. A guide that never mentions the pump bill leaves you blind to the one running cost that actually exists, and to the easy move that all but removes it.
Second, they push you to undersize to save upfront. The collectors are the visible cost, so the obvious saving is to fit fewer of them. But a collector area below your pool surface cannot transfer enough heat, so you compensate by running the pump for more hours. The few hundred dollars you saved on mats come back as a higher electricity bill every season.
Third, they promise year-round warmth everywhere. Solar pool heating extends the shoulder months, and in warm northern climates it can run close to all year. In the southern states it cannot beat winter, because there is not enough sun in July to warm a whole pool. A guide that ignores your climate sells you a season you will not get. Numbers and seasons like these belong in a dated box, which is why every figure on this page is stamped with the date it was checked.
How solar pool heating is really priced
Expert analysis: the machinery behind the running cost
How it works, and the collector-area sizing rule
Solar pool heating is simple plumbing. A pump pushes your pool water up to black collector mats or tubes on the roof, the sun warms the water as it passes through, and it flows back into the pool. There are no certificates and no inverter, just surface area and flow. The one number that decides whether it works is the collector area against your pool surface. The rule of thumb is 80 to 100% of the pool area: a 32 m² pool wants roughly 26 to 32 m² of collectors. Push to the top of the range, or above it, if the roof is shaded, faces south, or you want a longer season. Size it right and the pump runs a normal day; size it small and the pump has to run far longer to move the same heat.
The running-cost truth: the pump is the cost, and solar makes it cheap
Because the heat is free, the only thing solar pool heating costs to run is the electricity to move the water. That is either your existing pool pump working longer or a dedicated booster pump, and either way it draws power for hours a day through the season. At a usage rate near 30 c/kWh that adds up. Here is the lever: the pool pump is a large, flexible daytime load. Run it in the middle of the day on your own rooftop solar and the energy you use is worth only the export you forgo, around 5 c, instead of 30 c off the grid. That six-to-one gap is what turns "cheapest to run" into "almost free to run".
Solar versus gas versus a heat pump: upfront against running
Every pool heating choice is a trade between what you pay to fit it and what you pay to run it. Solar has the higher upfront cost, a few thousand dollars of collectors, but the lowest running cost because the heat is free and only the pump draws power. Gas and electric-element heaters are cheap to fit and the most expensive to run, because you pay for every unit of heat they make. A heat-pump pool heater sits in between: it is efficient electric heating with a coefficient of performance around 5 to 6, so it makes far more heat than the power it draws, but it still pulls from the grid. If you swim across a long season, solar's low running cost wins; if you heat the pool briefly and on demand, the maths shifts.
Climate and season by state, and why a cover changes the maths
Solar pool heating tracks the sun, so your latitude sets your season. In Brisbane and the warm north it can run close to all year. In Sydney, Adelaide and Perth it stretches the shoulder months. In Melbourne, Canberra and Hobart it cannot beat winter, full stop. The highest-return upgrade in every climate is not a bigger collector array, it is a pool cover. Most of a heated pool's losses are evaporation off the surface overnight, and a cover stops that. A cover holds heat more cheaply than any heater adds it, so it widens your solar season for a fraction of the cost of more collectors, and it cuts the pump hours you need on the days you do heat.
What this costs real households
How "free" solar heat ends up on the power bill
The mechanism above is not theory. It is exactly how well-meaning owners turn cheap heating into a real cost.
They undersize the collectors to save upfront
An owner fits collectors at 60% of the pool area to shave a few hundred dollars off the quote. The pool never quite warms, so they run the pump two extra hours a day all season to compensate. The upfront saving is gone within a year or two, and it keeps costing every season after that.
They run the pump on grid power at the wrong time
The pump is set to run early morning and evening out of habit, on full grid power at 30 c. The same pump shifted to the middle of the day, on the household's own solar, would cost a fraction of that. Nothing about the heating changes, only the timer, yet the running cost falls by most of itself.
They skip the cover and chase a bigger system
Unhappy with the season, an owner pays for more collectors. The pool still loses most of its heat overnight to evaporation, so the bigger array spends its mornings replacing heat that a $200 cover would have kept. They bought the expensive fix for a problem the cheap fix solves better.
They expect winter swimming in the south
A Melbourne household assumes solar means a warm pool in July. It does not, because the sun is not there. Disappointed, they bolt on a gas heater and run it hard, and the "cheap" pool becomes one of the more expensive ones on the street. Realistic season expectations would have saved the second system entirely.
The insider insight
The cheapest "heater" is a cover, and the cheapest fuel is your own roof
Here is the part the brochures never put together. Two of the highest-return moves in pool heating have nothing to do with the heater you buy. The first is timing the pump: because your rooftop solar exports earn only a few cents at midday, every kilowatt-hour your pump uses then is nearly free, while the same kilowatt-hour at night costs the full grid rate. The second is the cover: most of a heated pool's heat does not radiate away, it evaporates off the surface overnight, and a cover stops that better than any heater can replace it.
The non-obvious truth: for most homes the choice of collector matters far less than two free habits, running the pump on midday solar and keeping a cover on overnight. Owners who get those right find an average solar system performs beautifully and costs almost nothing to run. Owners who skip them end up with a bigger system, a longer pump schedule, and a power bill that quietly erases the point of going solar in the first place.
The practical consequence: before you spend on a larger collector array or a backup gas heater, spend on a cover and move your pump timer to the middle of the day. Those two changes beat almost anything you can buy.
Grounded in the analysis
What you should actually do
Specific moves that follow from how solar pool heating is priced, not generic advice.
Size collectors to 80-100% of pool area
Do not undersize to save upfront. Match collector area to your pool surface, and go to the top of the range or above it if the roof is shaded, faces south, or you want a longer season. A correctly sized system runs the pump a normal day instead of all day.
Run the pump on midday solar, not grid
Move the pump timer to the middle of the day so it runs on your own rooftop solar. The power it uses is worth only the ~5 c export you forgo, instead of ~30 c off the grid. Use the calculator above to see the season saving for your pump.
Add a cover, and set a realistic season
A pool cover is the cheapest heater there is: it stops the overnight evaporation that loses most of your heat. Expect a longer shoulder season in the south and close to year-round in the warm north, and do not buy a bigger system to fight winter.
See how rooftop solar panels are priced to power that pump, or read about solar hot water for the house.
Current figures, last updated 2026-06-15
Australian solar pool heating figures for 2026. Sources: the Clean Energy Regulator (STC scheme scope), the Australian Energy Regulator (DMO 2025-26 usage rates), the Essential Services Commission (VDO) and typical installer pricing. Confirm current figures before purchase, as rates and any local incentives are reviewed regularly.
The bottom line
Why this matters right now
Solar pool heating remains the cheapest way to run a warm pool, but only if you treat it as what it is: free heat that still needs a pump, over a season your climate decides. Size the collectors to 80 to 100% of your pool so the pump runs a normal day, move that pump to the middle of the day so it runs on your own solar at a few cents instead of grid power at thirty, and keep a cover on overnight so you are not heating water that evaporates away. Do that and the collectors are almost the least interesting part of the system, which, for running cost, is exactly the point. Set the season you can realistically expect, and let the cheap fixes do the heavy lifting before you ever reach for a bigger or a backup heater.
Common questions
A Selectra expert answers your solar pool heating questions
Installed, most systems sit between about $2,500 and $6,000, depending on the size of your pool, the roof and the collector type. Rubber or plastic mat collectors sit at the cheaper end; rigid glazed panels cost more but hold heat better in cooler weather. The collectors are the upfront cost. The ongoing cost is just the pump electricity, which is why solar is the cheapest pool heating to run once it is installed.
Almost, but not quite. The heat from the sun is free, but a pump has to push your pool water up through the collectors and back, and that pump draws electricity. At a typical usage rate near 30 c/kWh that running cost is real, especially if the collectors are undersized and you run the pump longer to compensate. Run the pump in the middle of the day on your own rooftop solar instead of grid power and the running cost drops close to zero, because the energy you use is worth only about 5 c as an export.
The rule of thumb is a collector area of about 80 to 100% of your pool's surface area. So a 32 m² pool wants roughly 26 to 32 m² of collectors. Go to the top of that range, or above it, if the roof is shaded, faces south, or you want a longer season. Undersizing to save a few hundred dollars upfront usually backfires: a small system has to run the pump for far more hours to deliver the same warmth, turning the saving into a higher electricity bill.
Solar is the cheapest to run because the heat itself is free and you only pay for the pump. Gas and electric-element heaters cost the most to run because you pay for every unit of heat. A heat-pump pool heater sits in between: it is efficient electric heating with a coefficient of performance around 5 to 6, but it still draws grid power. The trade-off is upfront versus running: solar has a higher upfront cost and a long, low-cost life, while gas is cheap to fit and expensive to run.
It depends on your climate. In warm and northern areas like Brisbane it can run close to all year. In the southern states it extends the shoulder months rather than beating winter, because there is not enough sun in July to warm a whole pool. The highest-return move in any climate is to add a pool cover. A cover cuts evaporation and heat loss more than any heater adds, so it stretches your solar season far cheaper than a bigger collector array would.
Generally no. The federal Small-scale Technology Certificate (STC) scheme rewards systems that generate power or approved solar water heaters, not pool heating, so do not expect the panel-style upfront discount you see on rooftop solar. Some states or councils have run pool-efficiency or cover incentives from time to time, so it is worth a quick check with your local council, but treat any rebate as a bonus rather than part of the sums [verify: current state and council pool-heating incentives].
