Answer
Apr 07, 2026 - 11:41 AM
The cost to run a 400,000 BTU pool heater depends on the type of fuel used (natural gas or propane) and local energy prices. On average, a 400,000 BTU gas heater uses about 4 gallons of propane or 4 therms of natural gas per hour, costing roughly $12–$16 per hour for propane or $4–$8 per hour for natural gas, depending on current rates. Your total cost will depend on how many hours you run the heater and your local fuel prices.
