The short answer
An outdoor tankless heater mounts on an exterior wall and vents straight from its cabinet, so there is no vent pipe or wall penetration for exhaust. That saves cost and indoor space. Where winters freeze, the exposed water lines are the weak point: follow the maker's freeze-protection instructions, keep power to the unit, and protect the connections with a pipe cover.
Units in the catalog
Rheem RTG-95XLN-3 199,900 BTU Natural Gas Outdoor Tankless Water Heater, Rheem RTG-95XLP-3 199,900 BTU Propane Outdoor Tankless Water Heater and Camplux WA686LP 199,000 BTU Propane Outdoor Tankless Water Heater.
Placement checks
- Clearances from windows, doors and vents in the manual.
- A level, solid wall within reach of the gas and water lines.
- Power for the electronics and freeze protection.
Products mentioned
Outdoor gas tankless · Rheem
Rheem RTG-95XLN-3 199,900 BTU Natural Gas Outdoor Tankless Water Heater
199,900 BTU/h · 9.5 GPM max
Outdoor gas tankless · Rheem
Rheem RTG-95XLP-3 199,900 BTU Propane Outdoor Tankless Water Heater
199,900 BTU/h · 9.5 GPM max · Propane
Outdoor gas tankless · Camplux
Camplux WA686LP 199,000 BTU Propane Outdoor Tankless Water Heater
199,000 BTU/h · 8.4 GPM max · Propane
Questions readers ask
Can a tankless water heater go outside in a cold climate?
Outdoor models are built for it and include freeze protection that relies on power; follow the maker's instructions for your climate.