Noritz America Corp.’s NRC 98, part of the company’s EcoTough Series of gas-fired condensing tankless water heaters for residential applications, has an energy factor of 0.93, as well as the ability to create longer vent runs with PVC instead of stainless steel. Offering a maximum input of 180,000 Btu per hour, the water heater comes in two-pipe, direct-vent, and outdoor models, and features a high-efficiency, low-nitrogen oxide Ecoburner with nitrogen oxide emissions at 20 parts per million. A PVC adapter built into the water heater flue is capable of handling either a 3" vent run or, if used with an increaser fitting, a 4" run.