What a hot tub costs to run each month
Short answer: roughly $18 to $45 a month for a modern, well-insulated tub at the US average electricity price of 18.16 cents per kWh, and $73 to $109 for an older, larger one. The two numbers that decide yours are how many kWh the tub uses (mostly down to climate, insulation and the cover) and what you pay per kWh. Put your own price in the calculator below.
Hot tub running cost calculator
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How the calculation works
Monthly cost = kWh per month × price per kWh
If you work it out from the heater, the kWh come from this:
kWh per month = (heater kW × hours heating a day + pump watts ÷ 1,000 × pump hours a day) × 30.4
Example: a 4 kW heater that runs about 3 hours a day uses 12 kWh a day, or 365 kWh a month. At 20 cents per kWh that's $73 a month. Add a 40 W circulation pump running all day and you'd add about 29 kWh, or just under $6.
Where the kWh figures come from
We haven't measured any hot tubs ourselves. The presets in the calculator are the makers' own published figures:
| City | kWh a month | At 18.16¢ per kWh |
|---|---|---|
| Miami | 100 | $18.16 |
| Las Vegas | 122 | $22.16 |
| Tulsa | 166 | $30.15 |
| Seattle | 188 | $34.14 |
| Chicago | 210 | $38.14 |
Hot Spring says these came from a third-party lab in a controlled chamber. Real life adds things the lab doesn't: wind, a worn cover, long soaks, lid left open. Treat them as a well-kept, efficient tub's best case.
Jacuzzi's figures are broader estimates: 150 to 250 kWh a month for a modern, well-insulated tub, and 400 to 600 kWh for an older 8-person tub. Jacuzzi works them out at 18 cents per kWh as about $27 to $45 and $72 to $108 a month.
What you pay per kWh matters as much as the tub
The EIA's figures for August 2026 put the average US home price at 18.16 cents per kWh, but states vary a lot. Nevada was the cheapest at 12.72 cents and Hawaii the most expensive at 47.18 cents. The same 210 kWh tub costs about $27 a month in Nevada and $99 in Hawaii. That's why the calculator asks for your own price.
If your utility has time-of-use rates, the price per kWh may be lower overnight. Check your utility's off-peak hours and set the tub's heating and filter cycles to match, if its controls allow.
How standby rules keep newer tubs efficient
California's appliance rules (Title 20) cap how much power a portable electric spa can use just keeping warm with the cover on. For standard spas made since June 1, 2019, the limit is 3.75 × V2/3 + 40 watts, where V is the tub's volume in gallons, measured with the water at 102°F and the air at 60°F. For a 400-gallon tub that works out to about 244 watts, or roughly 178 kWh over a month of standby. UL notes Oregon, Connecticut, Washington and Arizona have adopted the same rule. There's no federal standard: the US Department of Energy says there are currently no energy conservation standards for portable electric spas.
A tub sold in those states should carry a label showing its standby result, which is a handy way to compare models.
Ways to cut the cost
- Look after the cover. Both Hot Spring and Jacuzzi put a tight, dense cover first, and say to replace it when it's cracked, sagging or waterlogged.
- Turn the temperature down a little. Jacuzzi says dropping it 1 or 2°F saves about 5 to 10%. Never go above 104°F.
- Use a lower setting when you're away. Jacuzzi suggests 90 to 95°F for trips longer than three or four days.
- Heat and filter off-peak if your utility charges less overnight.
- Switch jets and blowers off when you get out, as Jacuzzi suggests.
Common questions
How much does a hot tub add to an electric bill?
It depends mostly on how cold it gets, how well the tub and cover are insulated, and your price per kWh. Hot Spring's lab figures for a medium tub range from 100 kWh a month in Miami to 210 kWh in Chicago. Jacuzzi puts a modern, well-insulated tub at 150 to 250 kWh a month and an older 8-person tub at 400 to 600. At the August 2026 US average of 18.16 cents per kWh, that's roughly $18 to $109 a month.
Is it cheaper to leave a hot tub on or turn it off?
If you use it often, keep it on. Hot Spring says holding a steady temperature usually takes less energy than heating it back up. For trips of more than three or four days, Jacuzzi suggests dropping the temperature to 90 to 95°F rather than switching off. In freezing weather, check your owner's manual before switching a filled tub off.
Does a 120-volt plug-and-play tub cost less to run?
Not necessarily. A smaller heater draws less power at any moment but has to run longer to heat the same water, and it may not keep up in cold weather. Hot Spring's Jetsetter, for example, is listed with a 1,500 W heater at 115 V or a 6,000 W heater at 230 V. What you pay for is the total kWh, not the heater size.
What temperature should a hot tub be?
No higher than 104°F. That's the limit the Consumer Product Safety Commission and the CDC both give. The CPSC also notes thermostats can be off by up to 4 degrees, so check with a thermometer now and then.
Sources
- US Energy Information Administration, Electric Power Monthly, Table 5.6.A, released October 23, 2026 (August 2026 residential prices). Read November 10, 2026.
- Hot Spring, Leading energy efficiency (city kWh figures and test conditions), energy efficiency checklist and Jetsetter spec sheet. Read November 10, 2026.
- Jacuzzi, How to Lower Your Bills. Read November 10, 2026.
- California Energy Commission, Express Terms for Portable Electric Spas (Docket 18-AAER-02, TN 222395), and portable electric spas FAQ. Read November 10, 2026.
- UL, guide to portable spa energy efficiency requirements (June 11, 2019), and US Department of Energy, Portable Electric Spas. Read November 10, 2026.
- 104°F limit: US Consumer Product Safety Commission, CPSC Warns of Hot Tub Temperatures, and CDC, What You Can Do to Stay Healthy in Hot Tubs. Read November 10, 2026.