The 5.8 GPM 180,000 BTU LP Gas Tankless Water Heater helps provide a reliable hot-water supply with dual stainless-steel heat exchangers and a 3-phase, pre-mixed burner. It operates only when needed and has an automatic shutoff valve to help you save on utility bills. Energy Star certification qualifies this heater for added energy and cost savings. A leak detector is built-in for your peace of mind. Also includes Circulation Pump with Mini Buffer Tank minimizing hot/cold/hot stacking, the so called Cold Water Sandwich.