HDPlumbing store AO Smith Residential Natural Gas Tankless Water Heater Non-Condensing Residential/Light Duty Commercial. 12 Year limited warranty heat exchanger, 5 year parts (residential). Energy star, indoor & outdoor models, Low NOx emissions, Copper Heat exchanger. Steel venting . BTU min 11,000, Max 199,000, energy factor .82, 7.2 GPM @45 deg rise. wt 45 lbs. List $1842. Ship to US Lower 48 only. Powered by eBay Turbo ListerThe free listing tool. List your items fast and easy and manage your active items.