Designed for two-bath homes in warm climates, the RTG-66X outdoor tankless water heater is capable of delivering hot water at a flow rate of 6.6 gallons per minute. It offers a lower firing threshold for summertime performance, so it will activate with a hot water demand of only 11,000 BTU per hour. Measuring 23 5/8 inches high, 13 7/8 inches wide, and 8 7/8 inches deep, the unit is also pre-programmed for high-altitude use. Rheem Manufacturing Co