With more than 2X the warranty of most traditional atmospheric tanks, and new features that simplify installation and boost performance, the new Demand Duo R-Series Commercial Hybrid Water Heating System is a better cost-effective alternative to standard efficiency tanks that easily installs in apartments, hotels, restaurants and more! NO Thermal Stress, Extended Service Life, Integrated Pump Control, 100% Tank Capacity, 100-200 lbs. lighter than most tanks, and $250 estimated Installation savings provide unmatched performance and low cost of ownership.