What Size Pool Heater Do I Need?

The size of swimming pool heaters you need depends on your pool’s size, desired water temperature, and how quickly you want it heated. A general rule is to multiply the pool’s surface area by the temperature rise needed, then multiply by 12 to get the BTU rating. For example, a 400-square-foot pool needing a 20°F rise would need around 96,000 BTUs. Climate and usage frequency also matter—colder areas may require a larger heater. For expert guidance and reliable installation, Ultimate Fountain and Pools offers professional advice to help you choose the perfect heater tailored to your specific pool needs.