Pool Heater Output for a Target Heat-Up Time
The heater output needed to warm a pool by a rise in a target time.
Example
You enter
- Pool volume (gallons) 20000
- Temperature rise (°F) 10
- Target heat-up time (h) 5.2125
- Efficiency (0.80 gas; COP-equiv HP) 0.8
You get
- Required heater output 400000 Btu/h
Details, formula, and sources
output = (gallons x 8.34 x rise) / (target_hours x efficiency). Warming a 20,000 gal pool +10 F in 5.2 h at 80% needs a 400,000 Btu/h heater; ask for it in 3 h and it jumps to 695,000 Btu/h. Answers 'what size heater do I need' instead of the time from one heater. Ignores cover/standby losses, so add margin. The equipment ratings govern.
Q_btu = gallons x 8.34 x dT; required_output_btu = Q_btu / (target_hours x eff); the inverse of hours = Q_btu / (output x eff).
The sensible water-heating relation (1 Btu raises 1 lb of water 1 F) solved for the heater output, by name.
The water-heating energy relation and the 8.34 lb/gal constant are standard published values. The equipment ratings and site conditions govern.
Estimate. AHJ and licensed professional govern.
Field names used by the API: gallons, dT_F, target_hours, eff, required_output_btu
- Sensible heat Btu = gallons x 8.34 x dT; 1 Btu raises 1 lb water 1 Fthermodynamics
- Output inverse output = energy / (target_hours x efficiency); enter COP-equiv Btu/h for a heat pumpequipment ratings
- No standby loss ignores cover/evaporation/standby losses; add margin for real heat-upscope of this tile