100,000 to 150,000 BTU is the sweet spot for most above-ground pools

Get a heater rated for at least 100,000 BTUs, and you’re safe for 99% of above-ground setups.

Above-ground pools are smaller — typically 10,000 to 15,000 gallons. The rule of thumb is 1 BTU per gallon per hour to raise the temperature 1°F. So a 100,000 BTU heater can bump a 10,000-gallon pool by about 10°F in an hour. If you’re in a colder climate or want faster warm-ups, bump up to 150,000. Oversizing isn’t wasteful — it just heats faster and shuts off sooner.

Don’t overthink it. Stick to 100k–150k BTU, match the gas line size, and you’ll be swimming comfortably.