How much electricity does a pool pump use?
More than its horsepower suggests. The HP on the label is the motor's shaft output; what you pay for is the electricity going in, which is higher by the motor's losses (the induction motors in single-speed pumps run around 70–75% efficient) and by the service factor that lets the motor run above its nameplate. The practical result is that a "1 HP" pump draws about 1,500 watts, not 746. Typical electrical draw by nameplate size, and what eight hours a day of it costs at $0.17/kWh:
| Single-speed pump | Typical draw | kWh per day (8 h) | Per month | Per year, 12 months |
|---|---|---|---|---|
| 0.5 HP | 900 W | 7.2 kWh | $37 | $447 |
| 0.75 HP | 1,150 W | 9.2 kWh | $48 | $571 |
| 1 HP | 1,500 W | 12 kWh | $62 | $745 |
| 1.5 HP | 1,900 W | 15.2 kWh | $79 | $943 |
| 2 HP | 2,300 W | 18.4 kWh | $95 | $1,142 |
| 2.5 HP | 2,700 W | 21.6 kWh | $112 | $1,340 |
| 3 HP | 3,100 W | 24.8 kWh | $128 | $1,539 |
Mid-range figures for common residential single-speed pumps; your model's draw depends on its motor and on how much plumbing it's pushing against. Two-speed pumps on low, and variable-speed pumps at any speed you'd actually run, draw a fraction of these — see below.
In order of trust: a variable-speed pump's own display shows watts at the current speed, and that's the real answer. Failing that, the motor's data plate lists amps at its voltage (usually 230 V, sometimes 115); amps × volts is an upper bound, because nameplate amps are the service-factor maximum and a pump on a normal plumbing run draws 10–20% less. Failing that, use the HP table above. Plug-in power meters mostly can't help — pool pumps are hard-wired 230 V — but watching your utility meter for ten minutes with everything else off works, and so does a clamp ammeter on one leg at the timer.
How much does it cost to run a pool pump per month?
Hours are the lever you control without buying anything. The bill is simply watts × hours × rate, which makes it a table you can read your own schedule off — monthly cost at $0.17/kWh:
| Pump | 4 h/day | 6 h/day | 8 h/day | 12 h/day | 24 h/day |
|---|---|---|---|---|---|
| 1 HP single-speed 1,500 W | $31 | $47 | $62 | $93 | $186 |
| 1.5 HP single-speed 1,900 W | $39 | $59 | $79 | $118 | $236 |
| 2 HP single-speed 2,300 W | $48 | $71 | $95 | $143 | $285 |
| Variable-speed at half speed 202 W | $4 | $6 | $8 | $13 | $25 |
30.4-day month. Scale by your rate: at $0.34/kWh every figure doubles. The variable-speed row is a 1.5 HP-class pump at half its top speed, from the affinity laws.
On a 1.5 HP single-speed pump at $0.17/kWh, each extra hour a day is about $10 a month — $69 over a seven-month season. "Run it 12 hours to be safe" instead of the 6–8 your turnover actually needs is $275 a season of safety you can't see in the water. The run time calculator works out the hours you actually need; on a variable-speed pump the same extra hour costs a tenth as much, which changes the whole conversation.
Single-speed, two-speed or variable-speed: the same water, priced
The fair comparison isn't watts against watts — it's the cost of moving the same daily water, because that's the job. Pump power falls with the cube of speed while flow falls only in proportion, so running slower for longer moves the same gallons for far less energy. A 1.5 HP-class pump turning over a pool in 8 hours at full speed, against the same water moved slower:
| Pump & speed | Draw | Hours for the same water | kWh per day | Per month |
|---|---|---|---|---|
| 1.5 HP single-speed | 1,900 W | 8 h | 15.2 kWh | $79 |
| Two-speed on low (½ speed) | 238 W | 16 h | 3.8 kWh | $20 |
| Variable-speed at 60% | 349 W | 13.3 h | 4.7 kWh | $24 |
| Variable-speed at 50% | 202 W | 16 h | 3.2 kWh | $17 |
| Variable-speed at 40% | 103 W | 20 h | 2.1 kWh | $11 |
Affinity-law estimates at $0.17/kWh; variable-speed rows include the ~15% efficiency edge of a permanent-magnet motor, two-speed low does not (it's the same induction motor). Real curves vary by model and plumbing — the shape of the answer doesn't.
That's the whole case for a variable-speed pump in one table, and it's also why the "how many hours" question flips once you own one: the hours become nearly free, so you run more of them, slower, and get better filtration and skimming for less money than the old 8 hours cost. The variable-speed savings calculator prices the upgrade on your pump and rate, with the payback in seasons. A two-speed pump captures a large share of the saving for less money — the budget middle path if yours still works.
Does running the pump at night save money?
Only if your utility charges less at night. On a flat rate a kWh at 2 a.m. costs what it costs at 2 p.m., and the schedule is purely about when the pool needs circulating. On a time-of-use plan the difference is real — off-peak rates are often half the peak rate — and since stabilized chlorine doesn't care what hour the water moves, shifting the run into the cheap window is free money; the calculator's off-peak field shows how much. Two reasons to keep some daytime hours anyway: a salt chlorinator only makes chlorine while water flows, and daytime is when it's being consumed; and during leaf and pollen season the skimmer earns its keep while debris is actually landing. Put the bulk of the run off-peak and an hour or two in the afternoon.
How to cut the pump bill, in order of payoff
- Run the hours the water needs, not a round number. One turnover a day is plenty for a residential pool; the run time calculator gives the hours from your volume and real flow. On a single-speed pump this is the only free lever, and it's worth $10 a month per hour at $0.17/kWh.
- Go variable-speed when the pump is replaced — or sooner if the payback above is short. US efficiency rules since 2021 mean most new pumps of about 1 HP and up are variable-speed anyway; utility rebates of $100–300 are common and shorten the payback.
- Move the run off-peak if you have time-of-use rates. Zero cost, immediate.
- Don't oversize the replacement. A 2 HP pump on a pool that needs 1 HP draws 2 HP's watts and moves water faster than the filter wants. Bigger is not better here; the right size moves the turnover in the hours you'd run anyway.
- Clean baskets and filter for flow, not for watts. A clogged filter or basket doesn't raise a single-speed pump's draw — a starved pump actually pulls slightly fewer amps — but it cuts the gallons each hour moves, so you end up running longer for the same turnover. The cost of a dirty filter is hours, not watts. On a variable-speed pump holding a flow setpoint, it's the reverse: the pump speeds up to compensate, and watts climb with the cube.
Rates vary more than pumps do: the US residential average is around $0.17/kWh, but Hawaii and parts of California run over $0.35 and parts of the Midwest and South under $0.12. Use yours — it scales every number on this page.
The rest of the pool's electric bill
The main pump is usually the largest single item, but rarely the whole story. A booster pump for a pressure-side cleaner is typically ¾ HP — around 1,000 W — and three hours a day of it is $16 a month; a robotic cleaner does the same job for a few dollars. A salt cell draws a couple of hundred watts while it's generating, so it's a small line. Lights are trivial if they're LED and not if they're 300–500 W incandescent run every evening. And a heat pump or electric heater dwarfs everything else on this list when it's running — the heating cost calculator prices that separately, and it's where the cover earns its keep.