Heater size planner
Turn gallons, temperature rise and deadline into a BTU-per-hour planning floor.
Open toolPool Heater Lab
Four calculators. Every assumption visible.
Use the result to frame a decision, then verify it against climate, the equipment pad and current manufacturer performance data.
Use ranges, not false precision
Pool-heating math begins with measurable inputs, but weather and evaporation keep real projects from behaving like a closed laboratory. Run a baseline with the values you know, then change one assumption at a time: a longer warm-up window, a cooler day, a cover or a different utility rate. The movement between scenarios reveals which decision matters most. Results stay in your browser and are intended for early planning; an installer and the current equipment documentation should settle final capacity, utilities, clearances and code requirements.