Pool Heater Size Calculator
Estimate pool-heater thermal capacity, input power, total heat-up energy and operating cost from pool volume, temperature rise and target heating time.
Default project preview
114,727 BTU/h
Thermal energy
807 kWh
Input power
39.6 kW
Input energy
949 kWh
Water volume
15,000 gal
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Pool water volume
Enter this project assumption in gal. The current imperial default is 15000 gal.
Target temperature rise
Enter this project assumption in °F. The current imperial default is 20 °F.
Target heat-up time
Enter this project assumption in hours. The current imperial default is 24 hours.
Heat-loss allowance
Enter this project assumption in %. The current imperial default is 10 %. Minimum: 0. Maximum: 100.
Heater efficiency or COP
Enter this project assumption in %. The current imperial default is 85 %. Minimum: 1. Maximum: 600.
Energy price
Enter this project assumption in per kWh-equivalent. The current imperial default is 0.18 per kWh-equivalent. Minimum: 0.
How to read the outputs
Thermal energy
heat delivered to water. Default preview: 807 kWh.
Input power
at 85% efficiency or COP equivalent. Default preview: 39.6 kW.
Input energy
heat-up cycle. Default preview: 949 kWh.
Water volume
entered volume. Default preview: 15,000 gal.
Heat-loss allowance
editable planning factor. Default preview: 10%.
Heat-up cost
entered energy rate. Default preview: $170.89.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Thermal energy = water mass × specific heat × temperature rise × loss factor. Heater capacity = thermal energy ÷ heating time. Input energy divides by efficiency or COP equivalent.
FAQ
Pool Heater Size Calculator questions
Why does a pool cover matter?+
Evaporation is a major heat-loss path, so a suitable cover can substantially reduce ongoing heat demand.
Is heater efficiency entered as a percentage?+
Yes. For heat pumps, an equivalent COP may be represented as a percentage above 100, such as 500% for COP 5.
Does this size gas piping or electrical service?+
No. Utility, venting, circuit and installation requirements need professional design.