Customer was convinced by someone that a noritz tankless domestic water heater set to 140°F would heat their home. He also had the main hot water for the home going through the coil and pump before coming to the faucets. He disconnect the furnace and connected the combustion for the noritz to the old flue. Needless to say, this home in Colorado did not get above 50°F in the winter. Customer has been using space heaters.