Abstract: A climate control system for a school bus, includes a frame having a cavity therein, a climate control unit secured within the cavity, and a removable cover plate. The frame extends through an exterior wall and into the passenger compartment of the vehicle. Removal of the cover plate permits access to the components of the climate control unit for service or replacement. In the preferred embodiment, the frame includes a casing having a top wall, a floor and three side walls, and the climate control unit is a heater having a filter, heat exchanger, and blower fan. Liquid coolant, warmed by the internal combustion engine of the bus, is circulated from the engine to the heat exchanger.