The ProLine® Vertex™ 50-Gallon Low NOx Power Vent Natural Gas Water Heater is designed specifically to generate a constant flow of 4 gallons per minute, resulting in continuous hot water for your home. Featuring a 50-gallon (nominal) tank and a 76,000 BTU gas burner, the GPHE-50 Power Vent delivers a thermal efficiency of 94%, a Uniform Energy Factor of 0.88, and a recovery rate of 95 gallons per hour. It carries a 6-year limited warranty, and meets Low NOx emission requirements. Environmentally-friendly insulation and factory-installed heat trap nipples reduce heat loss for maximum energy savings. This ProLine® XE water heater is designed with A. O. Smith's superior commercial-grade tank protection. Advanced tank features include stainless steel CoreGard™ anode rod, Blue Diamond® glass lining and DynaClean™ automatic sediment-cleaning system, all designed to help protect the tank from the corrosive effects of water and extend the life of the water heater. A. O. Smith’s ProLine® water heaters are residential products built to commercial-grade standards and are only available for purchase through professional wholesalers and contractors.