Hot tub
How much electricity does a hot tub use?
2,000–4,000 W · maintains heat 24/7 · $40–$120 per month
A hot tub is a large, hot, uncovered body of water sitting outdoors. Heat leaks out through the shell, the lid and evaporation, and the heater replaces it continuously.
What the bill is made of
- Standby heat loss: usually 60–80% of the total
- Heating from cold: a full heat-up is 30–60 kWh — expensive but rare
- Pumps and jets: 1,500–3,000 W while running, typically 1–2 hours a day
- Ozone / UV and controls: small, 50–150 W continuous
The four changes that matter
- Use a properly fitting insulated lid. An uncovered tub loses heat at several times the rate of a covered one. A warped or waterlogged lid is the most common cause of a high bill.
- Drop the setpoint to 37°C. Each degree above costs roughly 5–8% of heating energy.
- Use economy mode. Most tubs can filter during off-peak hours and heat only when needed rather than maintaining a fixed temperature.
- Insulate the shell and equipment bay if the model allows. Many mid-range tubs have almost no insulation underneath.
Is it worth owning?
A hot tub is a luxury with a running cost comparable to a second refrigerator times four. Knowing the monthly figure before buying is more useful than any feature comparison.
Frequently asked questions
How many watts does a hot tub use?
2,000–4,000 W. The figure on the rating label is the maximum draw; actual use varies with settings, age and usage pattern.
How much does it cost to run a hot tub per month?
With the defaults above it comes to the monthly figure shown in the calculator. At 16.5¢/kWh — the US residential average — that is a realistic middle estimate. Your own bill may be 30% lower or higher depending on state.
Is it cheaper to run a hot tub at night?
Only if your utility offers a time-of-use plan and you avoid the 4pm–9pm peak window. On a flat-rate plan, the time of day makes no difference to the total.
Does the calculator account for real-world duty cycles?
Not automatically — you enter the effective hours yourself. For compressing appliances like refrigerators and AC units, enter the running watts and roughly the proportion of time the compressor is on, which is usually 30–50%.
Will a newer hot tub actually save money?
Compare the kWh figure in the calculator against an Energy Star model's stated annual use. If the difference is a few hundred kWh a year, the payback on a replacement is usually long; if it is over 500 kWh, it is worth pricing out.