How Much Does a Hot Tub Cost to Run?
A typical hot tub costs $40–$60 a month in electricity at the US average rate. See what drives the number and how cover condition changes it.
A well-maintained modern hot tub costs $40 to $60 a month in electricity at the US average rate of 18.44¢/kWh — around $565 a year for a typical 250 kWh-per-month spa. A poorly insulated tub with a waterlogged cover in a cold climate can easily double that.
The wattage on the nameplate is misleading here more than for any other appliance. A hot tub heater is rated 5,000–6,000 W, but it only fires to replace heat the tub has lost. That duty cycle — typically 5–10% averaged across the year — is the entire story, and it is driven almost entirely by your cover, your climate, and how often you take the lid off.
- Per month
- —
- Per day used
- —
- kWh / year
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Where the money actually goes
Three loads share a hot tub's bill, and they are not equally important:
- The heater (roughly 70–75%). 5,000–6,000 W, firing in short bursts to hold the setpoint. Everything about reducing your bill comes back to making it fire less.
- The circulation pump (roughly 15–20%). Small, often 100–200 W, but frequently running 24 hours a day. Some tubs use a big two-speed jet pump for circulation instead, which is far more expensive.
- Jets, blower and lights (roughly 10%). 1,500–3,000 W but only while you are actually in the tub. Unless you soak daily, this barely registers.
That number is why "how often do you use it" is almost irrelevant to running cost, and why "what is your cover like" is almost the whole answer.
Monthly cost by state
Assuming 250 kWh a month — a realistic figure for a well-covered 400-gallon tub held at 100°F in a temperate climate:
| State | Rate | Cost | vs US avg | |
|---|---|---|---|---|
| Idaho | 12.35¢ | $379 | −187 | below average |
| Texas | 16.44¢ | $504 | −61.3 | below average |
| Florida | 15.17¢ | $465 | −100 | below average |
| Ohio | 19.52¢ | $598 | +33.1 | near average |
| Pennsylvania | 21.55¢ | $661 | +95.4 | above average |
| New York | 29.93¢ | $918 | +352 | above average |
| California | 33.25¢ | $1,019 | +454 | above average |
| Hawaii | 52.00¢ | $1,594 | +1,029 | above average |
The cover is the whole game
A hot tub cover is a foam panel wrapped in vinyl. Foam absorbs water. A cover that has taken on water loses most of its insulating value and gets heavy enough that people stop closing it properly, which compounds the problem.
Lift one side of the cover. A dry cover on a standard tub weighs 30–50 lbs and one person can flip it comfortably. If it takes two people, or if you hear sloshing, the foam is saturated. A waterlogged cover typically adds $25–$40 a month in winter — a replacement usually repays itself within a single heating season.
Cheaper fixes worth doing first:
- A floating thermal blanket under the hard cover. Around $40, cuts evaporative loss significantly, and evaporation is the largest single heat loss path on an uncovered surface.
- Check the cover seal. A cover that has warped and no longer sits flat leaks heat continuously along the gap.
- Insulate the cabinet. Older tubs often have bare panels with no insulation behind them at all.
Two expensive myths
"Turn it down when you're not using it"
Mostly false, and it is the most common hot tub advice on the internet. Heat loss is proportional to the temperature difference between the water and the air, so running cooler does save something — but a hot tub takes many hours and a great deal of energy to climb back to 100°F, and the reheat undoes most of the saving unless the tub sits cool for a long time.
The rule of thumb: lowering the setpoint pays off only if the tub will sit unused for more than about a week. For a tub used every weekend, leave it at temperature. Dropping it 5°F for a two-week vacation, on the other hand, is worth doing.
"Economy mode saves money"
Depends on the tub. On many spas, economy or sleep mode only allows heating during filtration cycles. That can save a little, or it can mean the tub is cold when you want it and then runs a long recovery cycle — which costs the same energy plus the inconvenience. Standard mode with a good cover beats economy mode with a bad one, every time.
Electricity is not the whole bill
Running cost estimates that stop at electricity understate ownership by a wide margin. Budget realistically:
| Cost | Per year | Notes |
|---|---|---|
| Electricity | $400–$900 | Climate and cover dependent |
| Chemicals | $150–$300 | Sanitiser, balancers, test strips |
| Filters | $40–$100 | Replaced every 12–24 months |
| Water | $20–$60 | Drained and refilled 3–4 times a year |
| Repairs / service | $100–$400 | Averaged; pumps and heaters do fail |
Call it $700–$1,700 a year all in, with electricity the largest and most controllable single line.
Frequently asked questions
How much does a hot tub add to your electric bill per month?
Typically $40–$60 a month at the US average rate for a modern, well-insulated tub. Expect $70–$110 in a cold climate or a high-rate state, and $100+ for an older tub with a saturated cover.
Is it cheaper to leave a hot tub on all the time?
For a tub used weekly or more, yes — leave it at temperature. Reheating from cold consumes roughly as much energy as was saved by letting it cool. Lowering the setpoint only wins if the tub will sit unused for more than a week.
Do hot tubs use a lot of electricity in winter?
Yes. Heat loss scales with the difference between water and air temperature, so a tub held at 100°F loses roughly three times as much heat at 20°F outside as at 70°F. Winter months commonly run double the summer figure.
Does a hot tub need a dedicated circuit?
Almost always. Most full-size spas require a 240 V, 50 A GFCI-protected circuit. Small 'plug-and-play' tubs run on 120 V/15 A but heat far more slowly and cannot run the heater and jets at the same time.
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