Bosch Greentherm C 1050 ES NG Natural Gas Tankless Water Heater, 199,000 BTU,10.5 GPM Suitable for indoor and outdoor installations 92% thermal efficiency 199,000 BTU maximum input 10.5 gallons per minute capacity at 35F&deg; rise Minimum activation flow rate of 0.65 gallons per minute Electronic ignition and patented burner design Exclusive safety and precision controls Direct vent, vertically or horizontally with Stainless Steel, PVC, CPVC or ABS-DWV Concentric and twin pipe venting options Can be used in solar thermal, recirculation applications Built for durability and servic