How much does it cost to run a 250-gallon inflatable hot tub per month?

Data checked October 2026

Short answer

A 250-gallon inflatable spa that meets California's standby limit costs about $45.92 a month to keep at 102°F — $551 a year (3,030 kWh) at the U.S. average 18.19¢/kWh.

California Title 20 caps a inflatable spa's standby power at 7 × V^(2/3) watts: 278 W for 250 gallons, measured covered with water at 102°F and normalized to a 37°F water–air gap.
Outdoors it peaks in January at $67.36 and falls to $27.37 in the warmest month (U.S. population-weighted normals).
Turning the water down 2°F to 100°F saves about $23.93 a year.
The hard-shell limit for the same volume is 189 W — hard-shell tubs are allowed slightly more at this small size.
Soaks with the cover off add more. Industry estimates for a full year of use run 1,500–3,500 kWh; many tubs also test well under the legal cap, so enter your tub's listed standby watts for a closer figure.

Adjust it to your exact job

Your hot tub

Type

Fill volume

gal

On the spec sheet or the tub's California Energy Commission listing (filled to mid-skimmer).

Standby power

Title 20 caps how much a covered spa may draw just to stay hot. Many tubs test well under the cap.

Settings

Water temperature

°F

Location

Electricity rate

Where the tub is

Price per kWh

EIA's state average: total residential revenue ÷ kWh sold, so delivery and fixed monthly charges are spread over every kWh.

250-gallon inflatable spa costs

$45.92a month on average

3,030 kWh a year · January up to $67.36 · $1.51 a day

At 18.19¢/kWh — U.S. average, Jan–Aug 2026 (EIA).

Per year: $5513,030 kWh
Coldest month (Jan): $67.36air 36°F
Standby rating: 278Wat a 37°F water–air gap
Average draw: 346Win an average U.S. climate

Monthly cost outdoors in an average U.S. climate

Turn it down a notch

Yearly cost by water temperature
Water	Per year	vs 102°F
98°F	$503	−$47.85
100°F	$527	−$23.93
102°F	$551	—
104°F	$575	+$23.93

What this includes

Keeping the covered tub at temperature, with its default filtration cycles — the condition California tests. Soaks with the cover off and jets running add more on top; industry estimates for a full year of use run 1,500–3,500 kWh.

Using the legal maximum

278 W is the most a 250-gallon inflatable spa sold in California may draw in standby. Enter your tub's listed rating for a closer figure.

How to cut it

Keep the cover on and replace it once it's waterlogged or sagging — the cover is part of the tested rating.
Heat loss grows with the gap between water and air: each degree lower saves roughly the share shown in the table.
Most of the year's cost lands in the coldest months — an enclosed or indoor tub sees a smaller gap; switch Location to compare.

Energy budget

3,030 kWh 250-gallon inflatable spa — keeping it hot for a yearcovered standby at 102°F, 18.19¢/kWh$551

Estimated total$551

Did this answer your question?

Compare

The same tub in colder and warmer states, at each state's Jan–Aug 2026 rate

State	¢/kWh	kWh a year	Per year	Coldest month
Minnesota	16.44	3,924	$645	$84.93
Colorado	16.8	3,719	$625	$72.23
New York	29.26	3,424	$1,002	$123.11
Ohio	18.81	3,377	$635	$79.52
Washington	14.42	3,391	$489	$52.59
Texas	16.03	2,316	$371	$48.12
California	32.58	2,745	$894	$95.63
Arizona	15.36	2,307	$354	$45.28
Florida	15.32	1,942	$298	$34.87

How this was worked out

250^(2/3) = 39.7; × 7 = 278 W at a 37°F gap. Heat loss through the cover and shell scales with the gap, so each month we multiply by (102°F − average outdoor temperature) ÷ 37 and by the hours in the month.

Prices: EIA average residential rates for Jan–Aug 2026. Outdoor temperatures: NOAA Climate Prediction Center population-weighted normals.

The full method, material data and tips are on the main hot tub cost calculator page.

Similar jobs

Other sizes people check

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

Sources

Data behind this answer

California Energy Commission — Title 20 portable electric spa standard (Docket 18-AAER-02) — max standby 3.75·V^(2/3)+40 W (standard spas), 7·V^(2/3) (inflatable), normalized to a 37°F water–air difference · checked October 2026
EIA Electric Power Monthly, Tables 5.6.A & 5.6.B — residential price by state (August 2026) — latest month and Jan–Aug 2026 year-to-date average for every state; preliminary, refreshed monthly · checked October 2026
NOAA Climate Prediction Center — population-weighted state degree days — monthly normal heating and cooling degree days by state (base 65°F) · checked October 2026
EIA Electric Power Monthly technical notes — average price = revenue ÷ sales, including fixed customer charges, fuel adjustments and surcharges · checked October 2026

Short answer

A 250-gallon inflatable spa that meets California's standby limit costs about $45.92 a month to keep at 102°F — $551 a year (3,030 kWh) at the U.S. average 18.19¢/kWh.

California Title 20 caps a inflatable spa's standby power at 7 × V^(2/3) watts: 278 W for 250 gallons, measured covered with water at 102°F and normalized to a 37°F water–air gap.

Outdoors it peaks in January at $67.36 and falls to $27.37 in the warmest month (U.S. population-weighted normals).

Turning the water down 2°F to 100°F saves about $23.93 a year.

The hard-shell limit for the same volume is 189 W — hard-shell tubs are allowed slightly more at this small size.

Soaks with the cover off add more. Industry estimates for a full year of use run 1,500–3,500 kWh; many tubs also test well under the legal cap, so enter your tub's listed standby watts for a closer figure.

Adjust it to your exact job

Your hot tub

Type

Fill volume

gal

On the spec sheet or the tub's California Energy Commission listing (filled to mid-skimmer).

Standby power

Title 20 caps how much a covered spa may draw just to stay hot. Many tubs test well under the cap.

Settings

Water temperature

°F

Location

Electricity rate

Where the tub is

Price per kWh

EIA's state average: total residential revenue ÷ kWh sold, so delivery and fixed monthly charges are spread over every kWh.

250-gallon inflatable spa costs

$45.92a month on average

3,030 kWh a year · January up to $67.36 · $1.51 a day

At 18.19¢/kWh — U.S. average, Jan–Aug 2026 (EIA).

Per year: $5513,030 kWh
Coldest month (Jan): $67.36air 36°F
Standby rating: 278Wat a 37°F water–air gap
Average draw: 346Win an average U.S. climate

Monthly cost outdoors in an average U.S. climate

Turn it down a notch

Yearly cost by water temperature
Water	Per year	vs 102°F
98°F	$503	−$47.85
100°F	$527	−$23.93
102°F	$551	—
104°F	$575	+$23.93

What this includes

Using the legal maximum

278 W is the most a 250-gallon inflatable spa sold in California may draw in standby. Enter your tub's listed rating for a closer figure.

How to cut it

Keep the cover on and replace it once it's waterlogged or sagging — the cover is part of the tested rating.
Heat loss grows with the gap between water and air: each degree lower saves roughly the share shown in the table.
Most of the year's cost lands in the coldest months — an enclosed or indoor tub sees a smaller gap; switch Location to compare.

Energy budget

3,030 kWh 250-gallon inflatable spa — keeping it hot for a yearcovered standby at 102°F, 18.19¢/kWh$551

Estimated total$551

State

¢/kWh

kWh a year

Per year

Coldest month

Minnesota

16.44

3,924

$645

$84.93

Colorado

16.8

3,719

$625

$72.23

New York

29.26

3,424

$1,002

$123.11

Ohio

18.81

3,377

$635

$79.52

Washington

14.42

3,391

$489

$52.59

Texas

16.03

2,316

$371

$48.12

California

32.58

2,745

$894

$95.63

Arizona

15.36

2,307

$354

$45.28

Florida

15.32

1,942

$298

$34.87

How this was worked out

Prices: EIA average residential rates for Jan–Aug 2026. Outdoor temperatures: NOAA Climate Prediction Center population-weighted normals.

The full method, material data and tips are on the main hot tub cost calculator page.