Grand Hall brings tank and tank-less technologies together in the first of its kind Eternal Hybrid water heater.. The patented and powerful Hybrid design replaces multiple tanks, uses less energy and space than one tank. and produces endless hot water on-demand. Small built-in storage tank eliminates cold sandwich and allows you to build a recirculation system without an external electric tank heater. Patented counter-fl ow design achieves 86% efficiency. The only on-demand water heater that can be PVC vented for easier, more economical installs . Exceeds SCAQMD low emission standards making Eternal one of the cleanest burning appliances of its kind. Stainless steel tank offers a lifetime no-leak warranty.