Navien NR-240 or NPE 240 Natural Gas TanklessHot Water Heater 199,000 BTU, installed. You will stop planning your mornings and evenings around your hot water heater and set your own schedule, thanks to the Navien NR-240-NG. The 98% thermal efficiency of the Navien NR-210-NG condensing technology stems from Naviens unique condensing design which incorporates two innovative stainless steel heat exchangers to achieve optimum heating value from every cubic foot of natural gas. The Navien NR-240-NG has a stainless steel secondary heat exchanger system that recaptures residual heat from flue gases to pre-heat incoming ground water. Some additional details about the Navien NR-240-NG or NPE 240 Natural Gas Tankless Water Heater include Suitable for mid-to large-sized homes with enough capacity for you to enjoy up to three plumbing and appliance outlets simultaneously, the NR-240 delivers up to 10 gallons of hot water per minute (GPM) at a 35 degree temperature rise, while saving energy and money. Mount your compact NR-240 or NPE 240 in virtually any room, andvent directly to the outside at a distance of up to 100 using 2 or 3 diameter schedule 40 PVC exhaust pipe or mount the unit on the outside of your home to free up interior space and save on installation and construction costs. Multiple units can be banked together for even greater capacity. The Navien NR-240-NG interior or exterior mounted, 10 GPM, Natural Gas, 98% Efficiency Condensing Tankless Hot Water Heater includes the Navien NR-10DU digital control. ULTRA-GREEN 98% EFFICIENT TANKLESS TECHNOLOGY 15 year heat exchanger warranty 5 years part warranty, 1 year labor warranty.