Fireplace Downdraft

The air pressure in the lower zones can be lower than atmospheric pressure and if the fireplace is located in one of these zones the chimney may have a permanent downdraft.

Fireplace downdraft. Basement fireplace backdraft as with backdrafting gas chimneys so it is for basement fireplace downdraft. The solution is to terminate the flue outside the negative pressure bubble or in less severe cases simply to open a window on the wind affected side to equalise pressures. When a downdraft occurs exhaust from the fireplace that should be vented outside the home backs up into the living space making your indoor environment not only uncomfortable but dangerous.

Once the chimney design is determined safe then the fireplace downdraft condition is most likely due to the stack effect as discussed above. In addition to turning off exhaust vents you should close all the windows in your home when using your fireplace. In days gone by a smoking fireplace was most likely to be caused by wind pressure on the house or surrounding trees or nearby buildings.

Using downdraft solutions like flue stretchers vacu stack chimney caps chimney fans and chimney draft inducers can help you eliminate smoke and excessive carbon monoxide gases in the home. That is if its location is below the neutral pressure plane. Before lighting your fireplace inspect all exhaust vents in your home to ensure they are turned off.

In reality true downdraft is extremely uncommon. Granted an open window alone typically isn t enough to create a downdraft. If an exhaust vent is turned on it will pull air your fireplace which could lead to a downdraft.