When we use the term ‘backdrafting’, it refers to gas in the flues reversing in direction which leads to combustion byproducts in the atmosphere in the home - this occurs within fuel-fired appliances.
Nowadays, there is a lack of an induced draft in fuel-fired boilers and water heaters. Essentially, this means that backdrafting is a common occurrence whenever low indoor air pressure is seen. For inspectors, it is important to notice the backdrafting signs in a home.
How? - Initially, you might be wondering exactly how this happens and we will start by saying the flue is used to remove all combustion byproducts outdoors. Found in boilers, furnaces, and water heaters, the idea is that the indoor air is much denser and so the heat and gases escape outdoors. Whenever there is unusually low pressure inside the home, this effect does not take place but instead the gases reverse and make their way into the room.
In truth, this can be extremely damaging and has been known to lead to medical conditions and even death. In addition to air pressure changes, this can also occur when flues are blocked.
Wonder if you have backdrafting issues? Contact us!
Mike McFadden, Certified Master Home Inspector in Orlando, FL