Rheem EcoSense 9.5 GPM 199,900 BTU Ultra LoNox LN Natural Gas Mid Efficiency Outdoor Tankless Water Heater A 9.5 GPM tankless water heater at a 35 degree temperature rise can provide enough hot water to supp Natural gas tankless water heaters heat water on demand, saving energy Outdoor installation eliminates the need for venting Compact space-saving design frees up valuable square footage No standing pilot means less wasted energy