Abstract: A dehydrator for improving energy efficiency and reducing the cost and air pollution associated with drying food products, such as grapes into raisins. The improved dehydrator utilizes the same basic structure as prior art dehydrators, which have multiple drying tunnels that each define a drying chamber in which the products are dried and a burn chamber in which a heat source heats air that is circulated to the drying chamber by a circulating fan. To reduce fuel consumption, the dehydrator of the present invention closes the openings into the tunnel, whereas currently only a front opening is closed, and utilizes a recirculating fan to draw heated air from the drying chamber for re-heating, at lower cost, by the heat source. A filter is used to remove moisture and contaminants from the recycled air and a diversion hood is used to direct the recycled air from direct contact with the heat source.