The main objective of the project is to make the combustion in a home furnace with a wood pre-oven more efficient so that the levels of harmful gases in the flue gas are minimized. This will be achieved by controlling the amount of combustion air available in the furnace by adjusting the primary and secondary air intakes. The control program running on a PIC microcontroller collects the input data from a number of sensors which measurers the flue gas and water temperatures. The system also has gas sensors which measurers the oxygen and carbon monoxide contents of the flue gas and also a couple of photocells that monitors the flames in the furnace. The user can check the system status on a LCD display and make adjustments to the system with a keypad.