A drying system (100) for use in drying out a water-damaged structure includes a blower (105) for providing outside air to the water damaged structure. An indirectly fired furnace (101) is used for heating the outside air prior to its introduction into the water-damaged structure. An exhaust blower (114) removes humid air from the water-damaged building, and one or more remote temperature and humidity sensors (117) are used for controlling the furnace air temperature and supply blower volume. An air intake filter box (111) is used for adding make-up air to recirculated building air and promoting cooling within accompanying trailer. A differential air pressure transmitter (118) controls the volume of moist air removed from the water damaged building to an optimal rate.