A pump's job is measured in litres, not hours

Filtration is measured in turnovers — how many times a day the whole pool passes through the filter. The industry standard is one a day, and two in hot weather or heavy use. It is not measured in hours, and the number of hours one turnover takes depends entirely on the pump.

Since 2022 every swimming pool pump sold in Australia has carried a GEMS energy label, and that label is calculated on exactly one 50,000 litre turnover a day. For the single-speed pump sitting beside most Australian pools, that takes about three hours. Most timers are set to eight.

Those extra five hours do not make the water cleaner. They turn the pool over two and a half times instead of once, and on the pump beside most Australian pools they roughly triple the bill:

Timer set toTurnovers a dayElectricityCost a yearVerdict
3 hours1.0×1,329 kWh$440Within the standard
4 hours1.3×1,771 kWh$586Within the standard
6 hours2.0×2,657 kWh$879Within the standard
8 hours2.7×3,543 kWh$1,173Filtering water that is already clean
10 hours3.4×4,428 kWh$1,466Filtering water that is already clean
12 hours4.0×5,314 kWh$1,759Filtering water that is already clean

A single speed, 1 star pump on a 48,000 litre pool, at New South Wales's rate. The filtration standard is one turnover a day, two in hot weather or heavy use, and this pump does one in 3.0 hours. Everything past that is money for nothing. Hours are calculated at the flow on the pump's energy label, which is measured at a standard resistance — real plumbing and a loaded filter both reduce flow, so add a margin.

Put your own pool in the calculator and it will tell you what your timer setting is actually buying.

Then the pump itself

Once the timer is right, the pump is the next question, and the gap between the best and worst on the market is larger than for any other appliance in the house. The reason is that pump power rises with roughly the cube of speed: run a pump at half speed and it uses about an eighth of the power to move half as much water. Take twice as long and you use a quarter of the energy.

That is the whole case for a variable speed pump, and it is why the slowest pumps in this table cost the least despite running nearly twice as long:

PumpDrawHours for one turnoverA yearCost a yearModels on the register
Variable speed, 7 stars204 W5.7 h426 kWh$1414
Variable speed, 6 stars212 W5.7 h442 kWh$14689
Variable speed, 5 stars233 W6.0 h514 kWh$17051
Single speed, 2 stars632 W4.0 h925 kWh$30615
Two speed521 W4.9 h933 kWh$30917
Single speed, 1.5 stars844 W3.6 h1,094 kWh$362194
Single speed, 1 star1213 W3.0 h1,314 kWh$435229

Every pump doing the same work — one turnover of a 48,000 litre pool a day, 365 days — at New South Wales's rate of 33.1c/kWh. The slow pumps run longer and still cost less, because pump power rises with roughly the cube of speed: halve the speed and you use about an eighth of the power to move half as much water. The spread from best to worst is $294 a year.

The star rating is not the number to compare

This one is worth knowing before you walk into a pool shop, because the label is easy to misread and nobody selling you a pump has any reason to explain it.

The consumption box on a pool pump's energy label is exact arithmetic on a single measured figure, the weighted energy factor, in litres moved per watt hour. Every one of the 662 pumps on the Australian register reproduces to the first decimal place. It is directly comparable between any two pumps.

The stars are not. They are banded separately for each type of pump, and the bands overlap so heavily that a rating means nothing across types:

Pump typeStar ratings awardedLitres moved per watt hourLabelled consumptionModels
Single speed1 – 2.5 stars11.1 – 20.7882 – 1,644 kWh439
Two-speed2.5 – 3.5 stars16.7 – 22.9797 – 1,093 kWh31
Multi speed4 – 6 stars24.7 – 35.0521 – 739 kWh16
Variable speed3.5 – 7 stars22.4 – 49.3370 – 815 kWh176

Read across rather than down. A two-speed pump rated 3.5 stars and a single-speed pump rated 2 stars overlap almost exactly on the only figure that matters — litres moved per watt hour — because the star bands are set separately for each type of pump. The consumption box on the label is comparable between any two pumps. The stars are not.

A two-speed pump advertised at 3.5 stars and a single-speed pump at 2 stars will use about the same energy to move the same water. Compare the kilowatt hours, not the stars.

What a suction cleaner does to a variable speed pump

This is the part nobody mentions, and for a lot of households it is the difference between a variable speed pump paying for itself and not.

A variable speed pump saves money by running slowly. A suction cleaner — the kind that crawls around the floor on the end of a hose — has no motor of its own and is driven by the filtration pump, which means the pump has to run up to drive it. The register publishes both figures for every product, and the gap is larger than most people would guess: the median 6-star variable speed pump draws 212 W filtering and up to 1,319 W at maximum. Six times the power, for every hour the cleaner runs.

The consequence is that with a suction cleaner, a pump's maximum draw starts to matter as much as its label — and the ranking can invert. On a 48,000 litre pool in New South Wales with the timer on eight hours, the 6-star variable speed pump comes third behind the 7-star and the 5-star, purely because those two have lower maximums. Swap the suction cleaner for a robotic one and the 6-star pump goes back to second and costs $200 a year less.

So if you are buying a variable speed pump, buy a robotic cleaner with it. The cleaner is what lets the pump stay slow, and the pump is only worth having if it can. The calculator models this directly — change the cleaner and watch the order change.

The maximum draw used here is the pump's rated maximum input power from the register. A suction cleaner may not need everything the pump has, so this is an upper bound on the penalty rather than a precise figure for your installation.

Heating is a separate decision, and a much larger one

Filtration costs a few hundred dollars a year. Heating a pool can cost several thousand, and what it costs depends more on where you live than on anything you choose.

State or territorySolarHeat pumpGasElectric element
New South Wales$120$1,103$2,112$6,069
Victoria$100$1,361$2,975$7,487
Queensland$102$649$1,322$3,568
South Australia$152$1,587$2,691$8,729
Western Australia$121$1,043$3,861$5,738
Tasmania$102$1,683no mains gas$9,254
Australian Capital Territory$134$1,922$3,292$10,572
Northern Territorynot needed

A 48,000 litre pool held at 28 °C from September to April, with a bubble cover, at each state's reference rates. Solar is not the same product as the other three: its running cost is only the booster pump, and it cannot hold a temperature through a cold, cloudy week. Darwin appears as “not needed” because the air there averages 28.5 °C across those months and the water is already at swimming temperature.

Two things in that table are worth stating plainly rather than leaving to be inferred. First, solar is not competing with the others: its running cost is only the booster pump, and it cannot hold a temperature through a cold, cloudy week. Second, an electric element heater is included because it is still sold, not because anyone should buy one — it buys one unit of heat per unit of electricity where a heat pump buys five and a half.

More on pool heating, or run the numbers for your own pool.

And a cover, which beats all of it

If you heat your pool at all, a bubble cover is the highest-return thing you can buy for it. The Australian Government puts the reduction in heat loss at up to 75%; the figures here use 70%, because a blanket only works on the nights it is actually on.

HeaterNo coverWith a bubble coverSaved
Heat pump$3,678$1,103$2,575
Gas heater$7,041$2,112$4,928
Electric element heater$20,229$6,069$14,161

Same pool, same season, same target temperature in New South Wales — the only difference is a sheet of bubble plastic. The Australian Government puts the reduction in heat loss at up to 75%; this uses 70%, because a blanket only works on the nights it is actually on. Nothing else you can buy for a pool returns this much. Solar heating is not in the table because a cover does not change what it costs to run — it changes how warm the pool gets and how long the season lasts, which is a bigger effect and not one this table is in the right units to show.

Frequently asked questions

How many hours a day should I run my pool pump?

Long enough for one turnover of the pool, and two in hot weather or heavy use. How many hours that is depends on your pump: a typical single-speed pump moves 48,000 litres in about three hours, while a 6-star variable speed pump takes closer to six because it is running slowly on purpose. The eight hours most timers are set to is two to three turnovers on a single-speed pump, which is filtering water that is already clean. Work from turnovers, not from a rule of thumb about hours.

Is a variable speed pool pump worth it?

Usually yes, and the sums are unusually clear because pump power rises with the cube of speed. Doing the same filtration work, a 6-star variable speed pump costs roughly a third of what the most common single-speed pump costs — the table above gives both figures at your own rate — and if your timer is currently on eight hours the gap is wider still. Against a supplied-and-installed price of roughly $1,300 to $2,200 that is a payback measured in a few years, and faster if you are over-filtering now. Two things before you buy, though. Fix the timer first: that saving costs nothing and it is often the larger of the two. And if you have a suction cleaner, budget for a robotic one as well, because a suction cleaner forces the pump onto high and takes most of the saving back.

Does a suction cleaner cost anything to run?

Not directly — it has no motor. But it is driven by the filtration pump, and the pump has to run up to drive it, which on a variable speed pump means going from around 200 W to over 1,300 W for as long as the cleaner is working. On a typical pool that is worth about $200 a year, and it is enough to change which pump is cheapest. A robotic cleaner runs on its own low-voltage supply for a few dollars a year and lets the filtration pump stay slow, which is why the two go together.

What is the cheapest way to heat a pool in Australia?

Solar, by an order of magnitude, because its only running cost is the booster pump that pushes water through the roof matting. But it cannot hold a set temperature — on a cold, cloudy week it delivers nothing. Of the systems that can, a heat pump wins everywhere, typically costing a third to a half of what gas costs for the same heat, because it moves heat rather than making it. Gas keeps one genuine advantage: it is the only option that will take a cold pool to swimming temperature by the weekend.

Does a pool cover really make that much difference?

Yes, and more than any equipment you could buy. Most of the heat in a pool leaves through the surface, and most of that goes as evaporation. Covering the surface stops it. The Australian Government puts the reduction in heat loss from a heated pool at up to 75%, and says a translucent bubble cover can warm an unheated pool by as much as 7 °C on its own. It also cuts the water you have to top up, and the chemicals that go with it.

Where do these figures come from?

The pump figures are medians of the 662 swimming pool pumps on the Australian GEMS register, published as open data by the Commonwealth. Each class here takes its labelled consumption and its labelled run time from the same registered product, so the pair describes a pump that actually exists — and setting the calculator to the label's own run time reproduces the labelled figure exactly. The heating model is fitted rather than measured, and the methodology page says exactly what it was fitted to and how far to trust it.