Operating at 95% thermal efficiency, the Rheem SPIDERfire gas commercial water heater can deliver 460 gallons of hot water in one hour. The SPIDERfire features a patented heat-exchange system - a series of connected, elongated tubes immersed in the water tank. A burner at the top of the unit generates combustion gases, which then blow down a large main flue. The gases traverse through the elongated tubes two additional times, extracting as much heat energy as possible. The SPIDERfire is an efficient solution for commercial spaces with high demands for hot water, such as restaurants, hotels and laundromats.