Hot tub electricity cost calculator

What your hot tub adds to the electric bill each month, and where the money goes.

In short: Monthly kWh = (heater kW × heater hours + pump kW × pump hours) × 30.4. A 4 kW heater running 2 hours a day plus a 300 W pump for 12 hours uses about 353 kWh a month: about $60 at 17 cents.

Formulas reviewed November 1, 2026 · How we calculate

Your pool

$59.95 a month

About 353 kWh a month, or $719 a year. The heater is 69% of it.

Heater per month
243 kWh
Pump per month
109 kWh
Per year
$719

What would change your result

  • Cutting heater time by 30 minutes a day, with a better cover or a slightly lower set point, saves about $10.34 a month.
  • Keep the water balanced: scale on the heater element makes it run longer.Open

Heater time depends heavily on weather, cover condition and how often the lid is open. Your bill is the best check.

Hot tub running cost chart

Monthly cost by heater power and daily heater time, plus a 300 W pump for 12 hours, at 17 cents per kWh.

Heater1 hour a day2 hours a day3 hours a day
1.5 kW$26.36$34.11$41.86
4 kW$39.28$59.95$80.62
5.5 kW$47.03$75.45$104

Getting it right

A wooden hot tub in a forest garden.
Photo: BlisswoodB&B, CC BY-SA 4.0

The heater is most of the bill. It runs to replace heat lost through the lid, the shell and every time the cover is open.

Find your heater's power on the spec sheet or the control box: most 240 V spas use 4 to 5.5 kW, plug-and-play 120 V tubs about 1 to 1.5 kW.

A good cover matters most. A waterlogged or cracked cover can double heater time. If yours is heavy or sags, replacing it pays back quickly.

Lowering the set temperature by a few degrees when you are away, rather than turning the tub off, avoids a long reheat.

Key facts

  • The heater uses most of a hot tub's electricity; the circulation pump is usually a small share.
  • A 4 kW heater running one hour uses 4 kWh, about 68 cents at 17 cents per kWh.
  • Covers lose insulation as they absorb water; a heavy cover is a sign it needs replacing.

How it's calculated

Heater energy = heater kW × hours a day × 30.4 days.

Pump energy = pump watts ÷ 1,000 × hours a day × 30.4.

The monthly cost is the total kWh times your price per kWh.

Questions people ask

How much does it cost to run a hot tub per month?

It depends mostly on how long the heater runs, which depends on climate and the cover. A 4 kW heater running 2 hours a day plus a small pump costs about $60 a month at 17 cents per kWh.

Is it cheaper to leave a hot tub on all the time?

Usually yes for regular use: keeping it warm with a good cover costs less than reheating from cold several times a week.

How do I lower my hot tub electric bill?

Replace a waterlogged cover, lower the set point when away, keep the water balanced, and run filter cycles off-peak if your utility has cheaper hours.

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