Hot Tub Running Cost Calculator
Estimate your spa's daily, monthly and yearly electricity cost.
Running Cost
How hot tub running cost is calculated
Electricity cost is energy used (in kilowatt-hours) multiplied by your rate. The formula here is daily cost = ((heater watts × heater hours) + (pump watts × pump hours)) ÷ 1,000 × rate per kWh. A typical setup -- a 1,500W heater running 4 hours a day and a 1,000W pump running 8 hours a day at $0.16/kWh -- costs about $2.24 a day, or roughly $68 a month.
Heater and pump run time vary a lot by climate, insulation, cover use and how often the spa is used -- a well-insulated spa with a good cover in a mild climate might need far less heater run time than this default, while a poorly insulated spa in a cold climate could need much more.
$0.16 per kWh is used as a reasonable US average default, but rates vary widely by state and utility, from under $0.10 in some regions to well over $0.30 in others -- check your latest electric bill for your actual rate.
Where these numbers come from
The formulas and default values in this calculator are based on:
- standard electricity cost formula (kWh x rate)
- $0.16/kWh used as a reasonable editable US average residential electricity rate (U.S. Energy Information Administration data ranges by state and year)
- default heater and pump wattages and run times reflect common residential spa equipment
These are planning estimates. Test your actual water, follow product labels, and check your equipment manufacturer's guidance before you buy or dose chemicals.
Frequently asked questions
Why do heater and pump run times vary so much between spas?
Ambient temperature, insulation quality, cover use, water temperature setpoint and how many hours a day the spa is in 'ready' mode versus economy mode all affect run time. Check your spa's control panel or manual for its typical daily heater and pump cycle if you want a more accurate estimate than the defaults here.
Does a higher temperature setpoint cost a lot more?
Yes -- a higher setpoint means more heat loss to the surrounding air (which scales with the temperature difference), so the heater cycles on more often to maintain it. Lowering your setpoint by even a few degrees when the spa isn't in regular use can meaningfully cut running cost.
Should I turn my spa off when not in use?
Most manufacturers recommend leaving a spa running continuously rather than powering it fully off, since reheating a fully cooled spa from scratch often uses more total energy than maintaining temperature, and prolonged shutdowns can affect water chemistry and equipment. A lower 'away' or economy mode is usually the better option for extended absences.
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