How Much Does It Cost to Run a Hot Tub?
About $49 a month for a 240V tub with a 4 kW heater at the 2024 US average rate of $0.16/kWh — about $597 a year. But the average hides the shape: the same tub runs near $65 in a winter month and $33 in a summer one. Set your own heater size, run-time and rate below.
Hours the element is actually on, averaged over the year — not hours the tub is switched on.
Average electricity cost per month
$49.10
10.2 kWh a day at $0.16/kWh, over a 30-day month — $597.35 a year. A hot tub never gets a month off.
A winter month
$65.44
35°F outside
An average month
$49.10
55°F outside
A summer month
$32.76
75°F outside
The same tub costs 2.0x as much to hold at 102°F in January as in July, because the water is fighting a much bigger temperature gap. Nothing about how you use it changed.
Where an average month goes
Monthly cost by load, at $0.16/kWh.
Holding the water at temperature
Filtering on a timer
The part you actually enjoy
Fine-tune the pumps and your soaking habit
Seasonal figures scale the heater's run-time by the gap between 102°F water and the outdoor air, holding your cover and insulation constant; the circulation and jet pumps do not change with the weather. Real tubs also lose extra heat every time the cover comes off, which this model leaves out. Months are 30 days. Not sure of your rate? Check average rates by state.
Average hot tub electricity cost per month
Monthly cost = (heater kWh + pump kWh + jet kWh) per day × 30 × price per kWh
A hot tub is three appliances on three different clocks. The heater replaces the heat the water gives up to the air, all day, every day. The circulation pump turns the water through the filter on a timer. The jet pumps only draw power while somebody is in the tub. Only the first one is expensive.
Worked example (4 kW heater on for 2 h/day, 150W pump for 12 h/day, 3 half-hour soaks a week, $0.16/kWh): 8.0 + 1.8 + 0.4 = 10.2 kWh a day × 30 × $0.16 = $49.10 per month.
Heater wattage sets the run-time, not the bill
Your tub loses a certain amount of heat each day, and the heater's only job is to put it back. A bigger element does that in fewer hours; it does not do it with fewer kWh. Every row below replaces the same 8 kWh of lost heat and lands on the same monthly cost — the 120V plug-and-play tub simply spends most of the day heating.
| Heater | Watts | Hours a day | Heater kWh/day | Cost per month |
|---|---|---|---|---|
| 120V plug-and-playCapped by a 15A outlet | 1,500 | 5.3 | 8.0 | $49.10 |
| 240V, 4 kWThe common hard-wired size | 4,000 | 2.0 | 8.0 | $49.10 |
| 240V, 5.5 kWLarger spa | 5,500 | 1.5 | 8.0 | $49.10 |
| 240V, 6 kWSwim spa / cold climate | 6,000 | 1.3 | 8.0 | $49.10 |
The number that actually varies between tubs is the heat loss itself — the kWh/day column. Insulation, cover condition, wind exposure and outdoor temperature set it. Heater wattage only decides whether the element replaces that heat in one long stretch or several short ones.
Monthly cost by heat loss and electricity rate
Columns are the heat the tub loses each day, which the heater has to replace. Rows are common US electricity rates. All figures include the 150W circulation pump and 3 half-hour soaks a week.
| Rate ($/kWh) | 4 kWh/day | 8 kWh/daybaseline | 12 kWh/day | 16 kWh/day |
|---|---|---|---|---|
| $0.10 | $18.69 | $30.69 | $42.69 | $54.69 |
| $0.13 | $24.29 | $39.89 | $55.49 | $71.09 |
| $0.16 (US avg) | $29.90 | $49.10 | $68.30 | $87.50 |
| $0.22 | $41.11 | $67.51 | $93.91 | $120.31 |
| $0.33 | $61.66 | $101.26 | $140.86 | $180.46 |
A poorly insulated tub with a waterlogged cover in a cold climate sits at the right of this table; a modern, well-covered tub in a mild one sits at the left. That spread is wider than anything your electricity supplier can do for you. Find your rate on the rates by state page.
Seasonal cost differences
Water at 102°F loses heat in proportion to how far above the surrounding air it sits. In July the tub is fighting a 27°F gap; in January it is fighting a 67°F one. That is the whole explanation for why the January bill roughly doubles — the heater simply runs longer to stand still.
| Season | Assumed outdoor temp | Temperature gap | Heater kWh/day | Cost per month |
|---|---|---|---|---|
| WinterDec-Feb | 35°F | 67°F | 11.4 | $65.44 |
| SpringMar-May | 55°F | 47°F | 8.0 | $49.10 |
| SummerJun-Aug | 75°F | 27°F | 4.6 | $32.76 |
| FallSep-Nov | 55°F | 47°F | 8.0 | $49.10 |
Outdoor temperatures are assumptions, not measurements — substitute your own climate and the shape of the answer holds. The four seasons average back to the $49.10 month and $597 year quoted above. Solar gain, wind and rain all push real numbers around this line.
The tub peaks when everything else does
A hot tub's worst months are December through February — the same months your furnace, your water heater and your lights are all working hardest. That is why hot tub owners so often report a shocking winter bill without a shocking summer one: the tub added $33 a month on top of every other seasonal load, not on its own.
Snow on the cover is not insulation
A cover keeps heat in only while it is dry and sealed. Once the foam core takes on water it conducts heat rather than blocking it, and a waterlogged cover in January is the single most expensive fault a hot tub can have. If your cover is noticeably heavier than it was new, that is what the winter bill is telling you.
Hot tub vs. pool pump
These are the two appliances most likely to be the largest line on a homeowner's electricity bill, and they fail in opposite ways. The pool pump is a big draw on a schedule you control, for part of the year. The hot tub is a small draw you cannot switch off, every day of the year, worst in winter.
| Appliance | Typical draw | Runs | kWh/day | Cost per month | Cost per year |
|---|---|---|---|---|---|
| Hot tub (average month) | 4 kW heater + 150W pump | Year-round, 12 months | 10.2 | $49.10 | $597 |
| Hot tub (winter month) | Same tub, colder air | Heater works 1.4x harder | 13.6 | $65.44 | — |
| 1.5 HP single-speed pool pump | 1,500W | 8h/day, 5-month season | 12.0 | $57.60 | $288 |
| Variable-speed pool pump | 250W on low | 12h/day, 5-month season | 3.0 | $14.40 | $72 |
All figures at $0.16/kWh. The pool pump rows assume a 5-month swim season and zero cost the rest of the year; monthly figures are for the months it runs.
The pool pump costs more per month; the hot tub costs more per year
A 1,500W single-speed pump on an 8-hour schedule bills $58in a running month, more than the tub's $49 average. But it spends seven months switched off, so its year lands near $288against the tub's $597. They are also fixable in completely different ways. The pump's cost is runtime and speed — a variable-speed model drops it to $72a year. The tub's cost is heat loss, and no pump upgrade touches it; only insulation, the cover and the setpoint do.
Tips to reduce hot tub energy use
The heater is 78% of the baseline bill, and everything it spends is replacing heat that escaped. So every worthwhile tip is about losing less heat — not about using the tub less. A 30-minute soak on the jets costs about 16 cents.
Check the cover before anything else
Most of a tub's heat leaves through the surface, and the cover is the only thing stopping it. Lift it: if it is heavy, sagging, or the seam has split, its foam has soaked up water and it has stopped insulating. Replacing it is the largest single saving available.
Drop the setpoint two or three degrees
Heat loss scales with the temperature gap, so each degree you come down saves roughly 2% of the heater's energy on an average day. Going from 102°F to 99°F is about $2.45 a month, and most people cannot tell the difference.
Add a floating thermal blanket
A thin sheet lying directly on the water blocks evaporation, which is where a large share of surface heat loss goes. It sits under the hard cover, costs very little, and does its best work in exactly the cold months when the tub costs the most.
Put the circulation pump on a timer
A 150W pump left running 24 hours costs $17.28 a month; on a 12-hour timer it costs $8.64. Most tubs only need to turn their volume over a couple of times a day to keep the water clear.
Break the wind, not the view
Moving air strips heat off the cover and off the water every time the cover is open. A fence, a hedge or a screen on the prevailing-wind side reduces standing loss for free, and it makes the walk from the door considerably shorter in February.
Don't bother switching it off
Bringing 400 gallons back from 60°F takes about 41 kWh and roughly 10 hours on a 4 kW heater. Shutting down for a weekend saves a couple of dollars and costs you the use of the tub. Shutting down for a month is a different calculation. More ideas in our energy savings guide.
Related Guides
Cost to Run a Pool Pump
The other big backyard load — and the one you can actually schedule
How to Save on Energy Bills
Practical tips by room with savings
Cost to Run a Water Heater
The same standing-loss problem, indoors and 40 gallons at a time
Hot Tub Cost Calculator
Quick watts-and-hours estimate on the main tool
Electricity Rates by State
Find your state's average rate
Most Efficient Appliances
See which appliances cost the most to run
Frequently Asked Questions
How much does it cost to run a hot tub per month?
About $49 a month for a 240V tub with a 4 kW heater at the 2024 US average rate of $0.16/kWh — roughly $597 a year. That assumes the heater replaces 8 kWh of lost heat a day, a 150W circulation pump on a 12-hour timer, and 3 half-hour soaks a week. Your number moves most with your electricity rate, your climate and the condition of your cover — not with how often you use the tub.
Does a hot tub cost more in winter?
Yes, by roughly double. Water loses heat in proportion to how far above the surrounding air it sits, so a tub held at 102°F leaks heat to 35°F winter air about 2.5x faster than to 75°F summer air. At the baseline above that is about $65 in a winter month against $33 in a summer one. Nothing about how you use the tub changed — only the temperature gap the heater is fighting.
Is it cheaper to leave a hot tub on all the time or turn it off?
Turning it off does save energy — a cooler tub leaks heat more slowly, and the heater can never spend more bringing it back than the tub lost while it sat. But the saving over a weekend is small, and the wait is not: reheating 400 gallons from 60°F back to 102°F takes about 41 kWh, or roughly 10 hours on a 4 kW heater. For anything shorter than a long vacation, lowering the setpoint a few degrees captures most of the saving with none of the wait.
Does a hot tub cost more to run than a pool pump?
Per year, usually yes — because it never gets a month off. A 1.5 hp single-speed pool pump running 8 hours a day actually costs more in the months it runs ($58 against the tub's $49), but it gets shut off for the winter. Over a full year the pool pump costs about $288 against the hot tub's $597. The tub's bill also peaks in exactly the months the pool's bill is zero.
How much does actually using the hot tub cost?
Almost nothing. A 30-minute soak with the jets running adds about 16 cents of electricity at $0.16/kWh. Across 3 soaks a week the jets account for roughly 4% of the tub's electricity; the heater accounts for about 78%. You are paying to keep the water hot, not to sit in it — which is why using the tub more often barely changes the bill.
How do I calculate my own hot tub cost?
Add the three loads. Heater: (heater watts ÷ 1,000) × hours the element is actually on each day. Circulation pump: (pump watts ÷ 1,000) × hours on the timer. Jets: (jet watts ÷ 1,000) × soak hours per week ÷ 7. Add them for kWh a day, multiply by your price per kWh, then by 30 for a month. The hard number to find is heater run-time — read it off the tub's control panel over a few days, or work backwards from a month of bills.