| Period | Hours | Energy | Cost |
|---|---|---|---|
| Fill in the fields above. | |||
How the calculation works
kWh = watts ÷ 1,000 × hours × days, then multiplied by your unit rate. Straightforward — but the interesting part is what happens when the pump slows down.
Pump power follows roughly the cube of speed, while flow follows speed directly. Halve the speed and you get half the flow for about an eighth of the power. Run for twice as long to move the same water and you have used roughly a quarter of the electricity. That is the whole case for variable-speed pumps, and it is why they have become mandatory on new installations in many places.
Worked example
A 1,500 W pump running 8 hours a day for 180 days uses 2,160 kWh. At 17 cents a kWh that is about $367 a year. The same pool filtered by a variable-speed pump at half speed for 16 hours would use roughly 540 kWh — about $92.
Assumptions
- The pump draws its rated wattage throughout. Real draw varies with head pressure and filter condition.
- The half-speed comparison uses the cube law, which is a close approximation for centrifugal pumps.
- Your electricity price is the unit rate you entered, excluding standing charges.
Limitations
- Time-of-use tariffs are not modelled. Running overnight on an off-peak rate can change the picture substantially.
- A single-speed pump cannot be slowed down — the comparison shows what a different pump would do, not what yours can.
- Heaters, salt cells and cleaners draw their own power and are not included here.
Questions people ask
How much does it cost to run a pool pump?
For a typical single-speed pump on an 8-hour schedule, a few hundred dollars a season at average rates — usually the largest single running cost a pool has. Enter your own wattage and rate above for a figure that means something.
Are variable-speed pumps worth the money?
On most pools they pay for themselves within two or three seasons, because power falls roughly with the cube of speed. The saving is large enough that many utilities offer rebates toward them.
Can I just run the pump fewer hours?
Only down to one full turnover. Below that the water is not being filtered properly, and what you save in electricity you tend to spend on chemicals and algae treatment.
Is it cheaper to run the pump at night?
On a time-of-use tariff, yes. But chlorine is consumed by daylight, so most people split the schedule — some filtration during the day, the bulk of it overnight.