The heat recovery system includes an oven having a treatment air with a treatment air temperature and a treatment air dew point temperature to treat a product or product in process. A zone outlet exhaust waste treatment air following the treatment of the product. A preheating zone includes a preheating inlet for the introduction of preheating air having a preheating air temperature and a preheating air dew point temperature to preheat the product. A transfer duct extends between the zone outlet of the oven and the preheating zone to transfer a portion of waste treatment air from the oven to the preheating zone to create the preheating air to preheat additional product. The preheating air preheats the product in the preheating zone to a product temperature that is at least equal to the treatment air dew point temperature to eliminate surface condensation on the product during treatment in the oven.