MasterTemp heaters are well-known for best-in-class energy efficiency and low emissions, even while heating your pool quickly. They feature an exceptionally compact design for such a high-performance heater, so they fit on smaller, less-intrusive equipment pads. Controls are intuitive and easy to use. MasterTemp heaters are also designed for super-quiet operation to help keep your poolside experience tranquil. On an medium sized inground pool, this heater will bring up your pool temperature approximately 1.5 degrees fahrenheit per hour. 

Pentair Mastertemp 300,000 BTU NatGas Heater