To provide a quick and easy tank replacement solution to contractors and end-users, Rinnai America Corp. has created the non-condensing Demand Duo R-Series Commercial Hybrid Water Heating System. Its design connects easily to the existing 6-inch B-Vent, allowing contractors to quickly replace standard-efficiency atmospheric tanks. The end-user, too, can benefit by simply upgrading to a system featuring part-tank and part-tankless design. Sold in 80- or 119-gallon tank options, the Demand Duo R-Series eliminates the need for new vent penetrations. The pre-installed drip leg and 36-inch Swivel-Flex Gas Line create material efficiencies and reduce install time with a pre-installed electrical junction box and duplex outlet. The digital controller, which comes with the product, allows management of building recirculation without having to purchase an additional aquastat.