Jandy EHE350PS Swimming Pool Heater Salt Water 350K BTU is the most popular pool heater among pros. It provides ultra-efficient heating with up to a 95% efficiency rating, cutting operating costs by 15% or more compared to 399K BTU heaters at 82% efficiency. Featuring a compact design, the Hi-E2 weighs in at 34% lighter than comparable heaters and with a 33% smaller footprint. The best option for retrofits, it’s easy to install, allowing for flexible indoor installation with direct PVC pipe connections.