Takagi T-KJr2-IN-LP Indoor Tankless Water Heater Maximum BTUs: 140,000 ; Minimum BTUs: 19,500 Vent Type: Direct Vent ; Water Connection Location: Bottom ; Water Connection: 3/4 Inch Heat Exchanger: Copper; Voltage: AC 120V ; UEF: 0.80 ;Emissions: Low Nox Product Weight:38 lbs 140,000 BTU 6.6 GPM max flow rate 4-Inch category III stainless steel venting required Inlet, outlet thermistors for constant temperature monitoring Energy factor of 0.81-0.83