Oil, wood, or gas burning appliances produce heat by burning fuel. Burning fuel produces combustion gases, which are normally vented to the outdoors through a chimney or vent pipe. Combustion spillage is the unwanted flow of combustion gases into the home. Combustion spillage (also known as backdrafting) occurs when a home becomes depressurized, and harmful combustion gases (such as carbon monoxide) are sucked back into the home through vents or a flue. Depressurization can happen when a home is very air tight and all exhaust fans, such as range hoods, bathroom fans, the dryer etc. are running at the same time, drawing air from the inside to the outside of the home. To learn more about combustions spillage, visit Natural Resources Canada’s website.
