The Jandy JXi Gas Pool Heater 260,000 BTU model is a highly efficient way to not just get your pool to your desired temperature, but to make sure it stays there. With a minimum GPM (gallons per minute) of 30 and a max GPM of 100, it can easily heat a pool with a surface area of up to 400 square feet. It sports high-temp poly headers and a copper heat exchanger — both of which contribute to its impressive efficiency rating of 84%. This means that 84% of the energy it uses during operation is actually being converted into heat, which helps to meet your needs while still keeping costs down. It’s an automation capable product that weighs 120 pounds, and it will require professional installation in order to be properly set up in your environment.