Navien NP-240 Commercial Condensing Tankless Water Heater with Pump and Buffer Tank, Natural Gas 98 percent thermal efficiency. 0.95 energy factor 17000 - 199000 BTU/hr Flow rates - At 35 Degree Fahrenheit Rise : 11 GPM, At 45 Degree Fahrenheit Rise : 8.6 GPM, At 77 Degree Fahrenheit Rise : 5.1 GPM Easy installation and PVC venting Includes NR-10DU remote control