Understand your estimate
How to use this result
A hot tub’s running cost is its daily electricity use multiplied by days and price. Daily use comes from a measurement over complete days, or from heater and pump power and actual on-time.
Method reviewed · Calculation methods · Evidence and source policy
Find the right inputs
Energy source
Measured kWh and days, or kW and on-hours
Prefer a submeter or plug-in meter reading over complete days. A timer window is not on-time.
Days in the period
Whole days
Use the days you want priced. Winter and summer use differ, so do not project one season over the year without saying so.
Your electricity price
GBP, USD or EUR per kWh
Enter major currency units; 28 pence means 0.28.
The calculation
Daily kWh = measured kWh ÷ complete days, or heater kW × heater hours + pump kW × pump hours + other kWh. Cost = daily kWh × days × price per kWh.
A worked arithmetic example
Illustrative arithmetic: 28 kWh measured over 7 days is 4 kWh a day. At $0.20/kWh that is $0.80 a day, about $24 for a 30-day month and about $292 a year at the same daily use. These values are assumptions, not a measurement of any hot tub.
What the estimate can tell you
The result is only as representative as the days measured. Cold, windy weeks and heavy use raise the heater’s on-time, and a well-fitting insulated cover reduces heat loss. Repeat the measurement in another season before relying on a yearly figure.
Questions about this calculation
Is the heater rating the same as its running power?
The heater only draws its rating while the element is on. Heater on-hours depend on the set temperature, weather, cover and use, so the average draw is lower than the rating over a full day.
Why is my measured daily kWh different from the published ranges?
Climate, cover, set temperature and use all change it, so published ranges are only a starting point. A measurement from your own tub in similar weather is the better input.