Pool Heater BTU & Heating Time Calculator
Enter pool gallons, the current and target water temperatures, and the heater's delivered heat to water in BTU per hour. The water-only estimate is gallons × 8.34 × degrees Fahrenheit rise ÷ delivered BTU per hour.
Illustrative example: Raising 15,000 gallons by 20°F with 300,000 delivered BTU/h takes about 8.34 ideal hours. Outdoor weather, evaporation, covers, cycling, and heat-pump conditions can lengthen actual time. Fuel input is different from delivered output.
Plan your heating project
Separate heating time from operating cost
Use the heating-time estimate to understand the energy needed to raise water temperature. Use fuel or electrical input and your own energy rate in the operating-cost calculator to estimate the associated charge.
Pool Heater BTU & Heating Time
Estimate the time to raise pool water from a measured temperature to your target using delivered heater output.
Ideal water-only time. Evaporation, weather, covers, cycling, and heat-pump conditions can change actual time. Enter delivered output, not fuel input.
