Noritz America’s NCC1991 condensing tankless water heater delivers a thermal efficiency of 94% with an input range of 16,000 to 199,900 Btu. This enables the unit to meet the hot water needs of larger residential applications, as well as a wide variety of commercial projects. Using a special Quick Connect cable, two NCC199-DV units can be coupled to provide an input of nearly 400,000 Btu with a turndown ratio of more than 36 to 1. This makes the NCC1991 ideal for applications where hot water demand can substantially vary over the course of a day or throughout the year. To obtain its 94% efficiency level, the NCC1991 uses a secondary heat exchanger made entirely of stainless steel, transferring heat from the exhaust gases to the water. This heat recovery process lowers the temperature of the flue gases, allowing an additional cost-savings benefit: The exhaust vent runs with less-expensive, installer-friendly PVC piping rather than the stainless-steel venting required by conventional tankless water heaters.