A method, system, apparatus, and/or device for preheating air for a rooftop air handling unit (RTU). The method, system, apparatus, and/or device may include a barrier system configured to surround the RTU. The barrier system may include a structure to provide a frame for the barrier system, a first barrier configured to connect to a first side of the structure, and a collector configured to connect to a second side of the structure. The method, system, apparatus, and/or device may include a duct configured to connect between the collector and a chamber. The method, system, apparatus, and/or device may include a chamber configured to connect to an air intake hood of the RTU. The chamber may include a first opening to receive air stored in the cavity, a second opening to receive external air, and a diverter configured to switch between a first position and a second position.