Rinnai manufactures tankless gas water heaters, gas boilers, direct vent heaters and vent free heaters. Only Rinnai offers the quality and reliability that is built on a 45 year history of innovation and improvements. Rinnai commands quality through in-house design, engineering and manufacturing, and insures your satisfaction with in-house support. Rinnai has over 30 million tankless water heater installations worldwide. They have been efficiently heating water since 1964, and selling heating appliances in the United States since 1974. Rinnai is the world’s largest gas appliance manufacturer.