Calculators / Pool
How much does a variable-speed pool pump save?
Put in your pool size and season. You get the kWh and dollars for a single-speed and a variable-speed pump, and the payback.
Updated · How we check our numbers
Switching to variable speed saves
$348 a year
Turning over 22,000 gallons 1.5 times a day for 8 months: about 3,193 kWh with a single-speed pump and 922 with an ENERGY STAR variable-speed one, at 15.3¢ a kWh. A $1200 pump pays back in 3.4 years.
- Single speed
- 3,193 kWh$489 a year
- Variable speed
- 922 kWh$141 a year
- Saved
- 71%
- Payback
- 3.4 years
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Estimate for planning only, not professional advice. Check the manufacturer’s instructions, your local code and a licensed professional before you buy, build or install. Use at your own risk. Terms.
days = 8 months = 243.2 days (ENERGY STAR: 8 months = 243.2)
single speed = 22,000 × 1.5 ÷ 2.5132 gal/Wh ÷ 1000 × 243.2 = 3,193 kWh
variable speed = … ÷ 8.7 gal/Wh … = 922 kWh
saved = 2,271 kWh × 15.3¢ = $348
ENERGY STAR: "reducing pump speed by one-half allows the pump to use just one-eighth as much energy." A variable-speed pump runs longer at low speed and moves the same water for far less power.
DOE efficiency standards for dedicated-purpose pool pumps apply to pumps made since July 19, 2021 (10 CFR 431.465), so an old single-speed pump is the one to compare against.
ENERGY STAR says covering a pool when it's not in use can cut heating costs by as much as 50% to 70%, and water loss by 30% to 50%.
Ask your electric utility whether it rebates ENERGY STAR certified pool pumps before you buy.
How we work it out
kWh a day = gallons × turnovers ÷ energy factor (gallons per Wh) ÷ 1,000
This is the formula in ENERGY STAR's Pool Pump Savings Calculator, with its figures: a 1 hp single-speed pump moves 2.5132 gallons per watt-hour, an ENERGY STAR variable-speed pump a weighted 8.7. Its default pool (22,000 gallons, 1.5 turnovers a day, 8 months) comes out at 3,193 kWh a year against 922, and so does ours.
Where the numbers come from
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Pool care
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