Pool Heat Pump Running Costs: What You'll Actually Pay
The numbers, worked out from real power draw figures, so you can check them against your own pool instead of trusting a brochure.
Not sure what size you need? Try our pool heat pump sizing calculator. Enter your pool size and postcode and it shows the right kW, running costs and the models that fit.
A pool heat pump costs roughly $70 to $100 a month to run on a covered 40,000 litre pool through the shoulder season, and $190 to $270 a month on the same pool with no cover, at 30 cents per kilowatt hour. Heating that pool from cold the first time costs about $30 to $50 on top. Peak summer is cheaper than both. A cold southern winter is dearer.
Those are the figures. Below is exactly how they are built, so you can swap in your own pool size and your own tariff and get a number you can trust.
The three numbers that decide your bill
Your running cost is your heat pump's power draw, multiplied by the hours it runs, multiplied by your electricity rate. Nothing else matters much. Everything people argue about online, brand, refrigerant, cabinet material, changes those three numbers a little. A pool cover changes them a lot.
Work through them in order and you will land within about 20 percent of your real bill, which is closer than any online calculator will get you.
What a pool heat pump actually draws
A 20kW pool heat pump draws between about 0.26kW and 5.3kW depending on the model and how hard it is working, which at 30 cents per kWh is 8 cents to $1.59 an hour. That spread is not a typo. An inverter idling on a warm pool and an on/off unit hammering away at full noise are doing genuinely different things to your bill.
These are the rated input power figures off the actual spec sheets for units in our range, not estimates.
| Model | Type | Power draw | Cost per hour at 30c/kWh |
|---|---|---|---|
| Fairland Aqua X Essential 17.1kW | Full inverter | 0.32 to 2.51 kW | 10c to 75c |
| Guardian Platinum 20kW | Full DC inverter | 0.26 to 2.78 kW | 8c to 83c |
| Guardian Eco Pro 20kW | DC inverter | 0.27 to 3.22 kW | 8c to 97c |
| Guardian Lux-V 20kW | Full DC inverter | 0.35 to 3.2 kW | 11c to 96c |
| SensaHeat ES Series 20kW | On/off | up to 3.26 kW | up to 98c |
| Midea M Series 20kW | On/off | 4.2 kW typical, 5.3 kW max | $1.26 to $1.59 |
Rated input power from manufacturer specifications. Electricity at 30 cents per kWh, current as of August 2026.
Note what the inverter column is telling you. A Guardian Platinum 20kW holding a warm pool sits near the bottom of its range at 8 cents an hour. It only reaches 83 cents when it is pulling a cold pool up. An on/off unit has one setting, and that setting is the top of its range every single minute it is on.
How many hours it runs is the part people get wrong
Runtime is set by how fast your pool loses heat, not by how big your heat pump is. This is the bit that catches people out. A bigger heat pump does not use more electricity over a season, it uses the same electricity in fewer hours, because it is replacing the same lost heat either way.
A covered 40,000 litre pool held at 28 degrees in a moderate Australian shoulder season loses roughly 55 kilowatt hours of heat a day. Uncovered, that same pool loses around 150 kilowatt hours a day, because evaporation off an open water surface is brutal and it happens all night while you sleep.
That gap, roughly three times the heat loss, is the single largest number on this page.
What it costs to hold the pool warm, month by month
Holding a 40,000 litre pool at 28 degrees costs about $70 a month covered and about $190 a month uncovered with an inverter heat pump, at 30 cents per kWh in a moderate shoulder season. An on/off unit adds roughly 40 percent to both figures because it runs at a lower efficiency point.
| Setup | Heat needed per day | Electricity used | Cost per day | Cost per month |
|---|---|---|---|---|
| Covered pool, inverter | 55 kWh | 7.9 kWh | $2.40 | About $70 |
| Covered pool, on/off unit | 55 kWh | 11 kWh | $3.30 | About $100 |
| Uncovered pool, inverter | 150 kWh | 21 kWh | $6.40 | About $190 |
| Uncovered pool, on/off unit | 150 kWh | 30 kWh | $9.00 | About $270 |
Based on a 40,000 litre pool of about 32 square metres held at 28 degrees, moderate climate, electricity at 30 cents per kWh. Figures current as of August 2026 and will vary with your climate, tariff and how warm you like the water.
Scale it to your pool. Double the surface area and you roughly double the bill. Peak summer, when the air is warm and the pool barely drops overnight, runs at about half these numbers. A Melbourne or Hobart winter can run at double or worse, which is why plenty of people simply switch off for July.
What it costs to heat the pool up from cold
Heating a 40,000 litre pool from 20 degrees to 28 degrees costs about $22 in pure electricity, and realistically $30 to $50 once you account for the heat it loses overnight while it climbs. It takes two to four days with a correctly sized unit, not an afternoon.
The maths is simple enough to do on your phone. Raising 1,000 litres by 1 degree takes 1.16 kilowatt hours of heat. So 40,000 litres by 8 degrees is 371 kilowatt hours of heat. Divide by a working COP of 5 and you get 74 kilowatt hours of electricity. Times 30 cents is $22.
This is a one-off cost at the start of the season, not a monthly one. Once the water is up, you are only paying to replace what leaks away, which is the table above. People fixate on the heat-up number and ignore the holding cost, which is backwards, because the holding cost is what turns up on every bill for the next six months.
The cover matters more than the heat pump you buy
A pool cover cuts your heat pump running costs by around two thirds, which is more than the difference between the cheapest and dearest unit we sell. An uncovered pool loses most of its heat through evaporation off the surface overnight, and your heat pump spends the next morning putting it back.
Spend $600 on a cover before you spend $2,500 upgrading to a better heat pump. The cover pays for itself in a single season on most pools. The upgrade takes three or four. If you take one thing from this page, take that one.
Why an inverter costs less to run
An inverter pool heat pump costs less to run because it slows down instead of switching off, and a heat pump running slowly is far more efficient than one running flat out. The Fairland Aqua X Essential 17.1kW is a clean example: its COP at full tilt is 6.6, and at half capacity it climbs to 10.3. Same unit, same pool, half the fuel bill per unit of heat.
An on/off unit cannot do that. It has full speed and stopped, so every hour it works is an hour at its least efficient operating point. The Midea M Series 20kW at $3,799 is still the best value unit we sell and we sell plenty, but it earns that with its purchase price, not its running cost. Full detail on the Midea 20kW page.
The tiebreaker is season length. Run six months a year and the inverter premium comes back. Switch on for a fortnight either side of summer and it never will. Be honest about which one you are before you spend the extra $2,500.
What COP tells you, and what it does not
COP is how many units of heat you get per unit of electricity, so a COP of 5 means 30 cents of power buys you $1.50 worth of heat compared with an electric element. It is the number that makes a heat pump worth owning, and it is also the number most abused in advertising.
A headline COP of 16 is measured at the manufacturer's easiest test conditions: warm air, warm water, a small temperature lift. Your pool in a cold September morning is not those conditions. The Guardian Platinum's COP falls from 16.4 to 7.5 across its own range at 27 degree air, and to between 7.9 and 5.3 once the air drops to 15 degrees. That lower figure is the one to budget on.
Use COP for comparing two units, not for predicting your bill. For predicting your bill, use the power draw and runtime tables above. Prices and specifications current as of August 2026.
Five things that quietly push the bill up
- No cover. Three times the heat loss, three times the bill. Nothing else on this list comes close.
- An undersized unit. A heat pump too small for the pool never reaches temperature on a cold snap, so it runs around the clock and still leaves the water cool. Our pool heat pump sizing guide covers the volume maths.
- Chasing 30 degrees. Every extra degree costs real money, and the higher you push, the faster the pool loses it. Most people are happy at 27 or 28.
- Running it on the wrong tariff. If you are on time of use, heating in the middle of the day rather than the evening peak can cut the cost of the same heat by a third.
- A filter pump running on a bad schedule. The heat pump only works when water is flowing through it. A poorly timed filtration schedule makes it start and stop pointlessly.
Which units are cheapest to run
The lowest running cost in our range comes from the full inverter models, led by the Guardian Platinum 20kW at $6,290 and the Guardian Lux-V 20kW at $7,990. For mid-size pools on a tighter budget the Fairland Aqua X Essential 17.1kW at $4,140 is a genuine full inverter and the value pick of the range.
Smaller pools and spas run cheaper again by simple arithmetic. A plunge pool holds a fraction of the water, so a Fairland Aqua X Essential 7.5kW at $1,950 or a Guardian Eco Pro 9kW at $2,690 will hold one warm for a few dollars a week. Prices are Waternex list prices in AUD including GST, current as of August 2026.
See the whole line-up in Heat Pumps for Pools & Spas, or compare against every other heating method in our guide to the cheapest way to heat a pool.
Frequently asked questions
How much does it cost to run a pool heat pump in Australia?
A pool heat pump costs about $70 to $100 a month on a covered 40,000 litre pool and about $190 to $270 a month on the same pool uncovered, at 30 cents per kilowatt hour in a moderate shoulder season. Peak summer runs at roughly half those figures and a cold southern winter can double them.
How much does a pool heat pump cost per hour to run?
A 20kW pool heat pump costs between 8 cents and $1.59 an hour to run at 30 cents per kilowatt hour, depending on the model and how hard it is working. A full inverter idling on a warm pool sits at the bottom of that range, while an on/off unit heating a cold pool sits at the top of it every minute it runs.
Does a pool cover really cut pool heat pump running costs?
Yes, a pool cover cuts pool heat pump running costs by roughly two thirds, which is a bigger saving than any difference between heat pump models. An uncovered pool loses most of its heat by evaporation off the open surface overnight, so the heat pump spends the next day replacing warmth that has already gone.
Is an inverter pool heat pump cheaper to run?
An inverter pool heat pump is cheaper to run, typically by around 30 percent against an on/off unit of the same size. An inverter slows down to hold temperature rather than switching fully on and off, and a heat pump running at part load is far more efficient. The Fairland Aqua X Essential 17.1kW, for example, lifts from a COP of 6.6 at full output to 10.3 at half capacity.
How much does it cost to heat a pool from cold with a heat pump?
Heating a 40,000 litre pool from 20 degrees to 28 degrees costs about $22 in electricity, or $30 to $50 in practice once overnight heat loss during the two to four day heat-up is counted. Raising 1,000 litres by 1 degree takes 1.16 kilowatt hours of heat, so you can scale that calculation to any pool volume.
Does a pool heat pump cost more to run in winter?
A pool heat pump costs considerably more to run in winter, because colder air lowers its COP at the same time the pool is losing heat faster. A unit delivering a COP near 7 at 27 degree air can drop to around 5 at 15 degree air, so the same heat costs about 40 percent more. In cold southern climates many owners switch off through July and restart in September.
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This guide is general information for Australian pool owners and is not a substitute for advice on your specific pool and site. Running costs are estimates based on typical energy prices and manufacturer rated figures, and vary with your pool, climate, tariff and usage. Pool heat pumps are electrical appliances and must be connected by a licensed electrician. Prices and specifications are current at the date of publication and change without notice.