A Rinnai wall furnace is an appliance that mounts on a wall and is designed to heat a specific room or part of a house. Rinnai wall furnaces are designed to help lower the cost of heating a home.
Because the furnaces are mounted in the rooms they are intended to heat, homeowners can control the number of rooms that are heated and the temperature to which those rooms are heated. Also, the furnaces do not require any ducting for the delivery of hot air or the removal of combustion by-products, since they are directly vented through the wall to the exterior.
Rinnai, a manufacturer of natural gas water heaters and furnaces, was incorporated in Japan in 1920 and expanded to North America in 1974.