Systems and method for controlling the flow of air through a mechanical draft system are disclosed herein. A pressure controller for controlling air pressure comprises an appliance controller configured to control the operation of a plurality of appliances, an intake fan controller configured to control the speed of an intake fan, and an exhaust fan controller configured to control the speed of an exhaust fan. The pressure controller also includes a processor configured to receive a differential pressure signal and to control the operation of the appliances, the speed of the intake fan, and the speed of the exhaust fan in response to the differential pressure signal.