Pool Pump Energy Cost Calculator

The circulation pump is usually the biggest electricity user at the pool. Estimate its cost from the motor’s horsepower, its efficiency, how many hours a day it runs, and your own electricity rate in $/kWh.

Estimate: results come from your inputs and standard values (8.34 lb/gal, pool geometry). Measure your pool and verify before relying on a number.

Calculator

HP
Nameplate horsepower of the motor.
Typical single-speed motor ≈ 0.9 (0–1).
h/day
Hours the pump runs each day.
$/kWh
From your power bill — no rate is stored.
Cost per day$1.49
Cost per month$44.76
Energy per day9.95 kWh (1.24 kW)

A 1.50 HP pump running 8.0 h/day draws 9.95 kWh ≈ $1.49/day (about $44.76/month) at $0.150/kWh.

For most pool owners the circulation pump — not the heater — is the single largest year-round electricity cost, because it runs for many hours every day through the whole season. This calculator estimates that cost from four inputs you control: the motor horsepower, its efficiency, the daily run time, and your own per-kilowatt-hour electricity price. Because the rate is yours, the result stays accurate no matter what utilities charge or how prices move.

The physics is straightforward: horsepower converts to kilowatts, kilowatts times hours gives kilowatt-hours, and kilowatt-hours times your rate gives dollars. One horsepower equals 0.746 kilowatts of shaft power, and dividing by the motor efficiency accounts for the electrical draw being larger than the useful output. The tool reports cost per day and per month so you can see the running total, and it makes the case for shorter run times and variable-speed pumps immediately obvious.

Formula

Convert horsepower to electrical power, multiply by run hours for energy, then by your rate for cost:

  • kW = HP × 0.746 ÷ efficiency
  • kWh per day = kW × hours
  • $ per day = kWh × rate  →  $ per month ≈ $/day × 30

The factor 0.746 is the exact kilowatts in one horsepower; dividing by efficiency turns useful output into the electricity actually drawn from the wall.

Worked example

A 1.5 HP single-speed pump at 0.9 efficiency, running 8 hours a day, at $0.15/kWh:

kW = 1.5 × 0.746 ÷ 0.9 = 1.243 kW
kWh = 1.243 × 8 = 9.95 kWh/day
$ = 9.95 × $0.15 ≈ $1.49/day (about $44.75/month)

Halving the run time to 4 hours, or dropping to a variable-speed pump at a fraction of the wattage, would cut that figure dramatically over a season.

Cutting the running cost

Two levers dominate pump running cost: how long the pump runs and how much power it draws. You need enough daily circulation to turn the water over and keep it clear — see the turnover tool — but many single-speed pumps are run far longer than necessary out of habit. Trimming run time to what turnover actually requires is the simplest saving.

The bigger structural saving is a variable-speed pump. Pump power rises steeply with speed, so running a variable-speed motor slowly for longer moves the same water for a small fraction of the energy of a single-speed motor at full tilt. If you are estimating a variable-speed pump, enter its actual low-speed horsepower or measured wattage rather than the nameplate maximum. Off-peak time-of-use rates are another lever: shifting run time to cheaper hours lowers the effective rate you type in. Because nothing is stored, updating the rate keeps the estimate correct for good.

Frequently asked questions

How much does it cost to run a pool pump?
A 1.5 HP single-speed pump running 8 hours a day at $0.15/kWh costs about $1.49 per day, or roughly $45 a month. Larger motors, longer run times, or higher rates push it up; variable-speed pumps push it down sharply.
Why divide by motor efficiency?
Horsepower is the useful shaft output. The motor draws more electricity than that because it is not perfectly efficient, so dividing the 0.746 kW/HP figure by the efficiency (about 0.9 for a typical motor) gives the real electrical draw.
Do variable-speed pumps really save money?
Yes, often a great deal. Pump power rises steeply with speed, so running slower for longer moves the same water for a fraction of the energy. To estimate one here, enter its low-speed horsepower or measured wattage, not the nameplate maximum.
How many hours a day should the pump run?
Enough to turn the water over at least once, and ideally to filter it thoroughly. Use the turnover calculator to find the flow and time your pool needs; running much longer than that mostly wastes electricity.
Can I lower the rate I enter?
If you are on a time-of-use plan, shifting pump run time to cheaper off-peak hours lowers your effective $/kWh. Enter that lower rate to see the saving. The tool never stores a rate, so it always reflects your current price.

Related calculators

Turnover / FlowFind the pump flow in GPM needed to turn over your whole pool within a target number of hours — the basis for sizing pumps, filters and daily run time.Filter SizeFind the minimum filter area for your flow rate using standard design rates for sand, cartridge and D.E. media — size the filter to match your pump flow.Heating CostEstimate the cost to heat your pool with gas or a heat pump using your own energy rate. Free calculator with the formula and a worked example.Fill CostEstimate what it costs to fill your pool from the gallons and your own water rate — priced per gallon, per 1,000 gallons or per CCF. No tariff stored.