Appliance running costs
Cost to run a hot tub
How much does a 3,000 W hot tub cost to run?
A 3,000 W hot tub switched on 24 hours per day at 27% duty cycle uses 19.4 kWh of electricity per day. At $0.180/kWh that is $3.50 per day, about $106.50 per average month and $1,278 per year — 7,100 kWh over the year. Those figures assume a typical wattage and a typical usage pattern; change any input below to match your own appliance and tariff.
Your inputs
Typical example — replace this 3,000 W default with your appliance’s actual rating for a better estimate.
A thermostat cuts this appliance out once at temperature — typical range around 27%.
No effect at 24 h/day: there are no switched-off hours. Include a continuous idle load in the duty cycle instead.
Use the total variable rate from your bill, including delivery charges per kWh.
$106.50
per month (30.44-day average month)
19.4 kWh per day at 3,000 W
- Per day
- $3.50
- kWh / month
- 592
- kWh / year
- 7,100
- Per year
- $1,278
Average power across 24 hours
810 W
Daily energy spread evenly over 24 hours. Includes standby draw during switched-off hours when entered.
Cost per running hour
$0.146
While the appliance is actually drawing power.
Effective duty cycle
27%
Share of switched-on time at rated power.
Method
- 3,000 W = 3 kW
- 3 kW × 24 h/day × 27% duty = 19.44 kWh/day active
- 19.44 kWh × 0.18 USD/kWh = 3.499 USD/day
- 3.499 × 30.436875 days = 106.505 USD/month
- 19.44 kWh × 365.2425 days = 7100.314 kWh/year
- 7100.314 kWh × 0.18 USD/kWh = 1278.057 USD/year
Monthly figures use a 30.44-day average month, 365.24-day average year.
Assumptions
- Electricity rate of 0.18 USD/kWh (editable).
- Calculations use a year of 365.2425 days and an average month of 365.2425 ÷ 12 = 30.436875 days, so twelve average months equal one year exactly. Displayed values are rounded to 365.24 and 30.44 days, and the rounded figures do not multiply out exactly.
- Duty cycle of 27% — the appliance draws rated power for that share of the time it is switched on.
- Rated power is treated as real power in watts, not volt-amps.
What can change the result?
- Outdoor temperature and season — the single largest factor
- Cover condition and insulation quality
- Setpoint temperature (each degree costs measurable energy)
- Whether the tub is left at temperature or cooled between uses
$106.50/mo · 592 kWh/mo
How a hot tub actually draws power
Almost all of a hot tub's electricity goes into replacing heat lost through the cover and shell, not into the time you spend in it. The heater element — commonly 3 kW to 6 kW — runs only when water temperature drops below setpoint, while a small circulation pump runs many hours a day at a much lower draw. Consumption is therefore dominated by outdoor temperature and cover quality, and roughly doubles between summer and mid-winter.
Set the duty cycle to represent the share of the whole day the heater element is energised, typically 15–20% in summer and 30–40% in winter. Because a spa is powered around the clock there are no switched-off hours, so the small continuous circulation-pump and controller load (roughly 60 W) is folded into the duty cycle instead: the 27% default is about 25% heater plus 2 percentage points for the pump. Jets and blowers are short-duration and add relatively little to the annual total.
Cost at different usage patterns
All rows use 3,000 W at 27% duty and $0.180/kWh. Only the hours change.
| Hours per day | kWh per day | Per day | Per month | Per year |
|---|---|---|---|---|
| 12 h/day | 9.72 kWh | $1.75 | $53.25 | $639.03 |
| 18 h/day | 14.6 kWh | $2.62 | $79.88 | $958.54 |
| 24 h/day | 19.4 kWh | $3.50 | $106.50 | $1,278 |
Cost across the typical wattage range
Units in this category typically range from 1,500 W to 6,000 W. All rows use 24 h/day at 27% duty.
| Power rating | kWh per day | Per day | Per month | Per year |
|---|---|---|---|---|
| 1,500 W | 9.72 kWh | $1.75 | $53.25 | $639.03 |
| 3,000 W | 19.4 kWh | $3.50 | $106.50 | $1,278 |
| 6,000 W | 38.9 kWh | $7.00 | $213.01 | $2,556 |
Worth knowing
Worth knowing
Your next decision
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- Why the rating plate overstates what this appliance usesDuty cycle and part-load operation, which set the figures above.
Your next decision
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Electricity cost tools
- Electricity cost calculatorWatts and hours in, cost per day, month and year out.
- Cost per kWh explainedThree different costs per kWh on one bill, and which one belongs in a calculator.
- Appliance wattage calculatorA configurable appliance list: what this combination draws, and what it costs.
- Watts to run a houseRunning, average and startup watts — separated, not averaged into one range.
Defaults on this page come from the published default registry and the formulas are documented in the methodology.