Vav Box With Hot Water Reheat is a device that uses hot water to heat air for use in HVAC systems. It consists of an inlet, an outlet, and one or more fans to force air through the system. The inlet receives cold air from outside and the outlet delivers heated air inside. Hot water is supplied to the unit to provide the necessary heating energy and is generally drawn from an on-site boiler. Vav Box With Hot Water Reheat increases the efficiency of HVAC systems by providing steady temperatures throughout a building and reducing energy costs.