Pool, Spa & Water Treatment Chemistry calculator

Pool Heater Energy Cost Calculator

Convert heating demand into fuel cost using heater efficiency and the current energy price.

What this calculator does

  • Estimate heater energy cost from BTU demand, heater efficiency, and energy price.
  • Use it before heating a pool or spa, comparing schedules, or quoting event warmups.
  • Turns heating energy demand, energy price, therms per kbtu into a practical $ result for pool heater energy cost.

Formula used

  • Energy cost = heating demand in kBTU x energy price x therms per kBTU x efficiency correction

Inputs explained

  • Heating energy demand: Divide total BTU demand by 1,000. BTU demand = pool gallons x 8.34 x desired temperature rise. For 20,000 gal and a 10 F rise, enter 1,668.
  • Energy price: Use current natural gas, propane, or heat pump equivalent rate per therm.
  • Therms per kBTU: Enter 0.01 for natural gas (100 kBTU per therm). For propane, use a propane-equivalent rate.
  • Heater efficiency correction: Enter 100 divided by heater efficiency percent. For 82% efficiency, enter 1.22.

How to use the result

  • Use it when planning pool, spa, aquatics, service-route, or water-treatment chemistry adjustments.
  • Use the result for planning math only. Follow product labels, health codes, local regulations, test-kit instructions, chemical safety rules, and qualified pool operator guidance before dosing water.

Common questions

  • What is the pool heater energy cost calculator for? Estimate heater energy cost from BTU demand, heater efficiency, and energy price.
  • What numbers do I need for pool heater energy cost? You need heating energy demand, energy price, therms per kbtu, heater efficiency correction. Use measured test results and the same pool, spa, tank, or treatment volume for every input.
  • How should I use the result? Use the result to check dose size, run time, flow, inventory, or operating cost before changing a treatment plan or purchase order.
  • What should I verify before acting? Verify water volume, units, chemical strength, product label directions, bather load, local code, and current test results. Retest after treatment and never mix incompatible chemicals.

Last reviewed 2026-05-12.