Due to modern homes being built air tight and weather-proofing sealing up the usual air infiltration routes, this is making smoke problems quite a common issue.

A fireplace in use has the tendency to exhausts household air until a negative pressure situation exists. If your home is moderately air tight, the easiest route for makeup air to enter the home is often your unused fireplace chimney.

Eliminate Your Smoke Problem And Potential For Carbon Monoxide Poisoning

While air is drawn down the unused flue, it will pick up smoke that is exiting nearby from a fireplace in use and will deliver the smoke to your living area. The best solution to your smoke problems is to provide makeup air into your house so that the negative pressure problem cease to exists. This will eliminate not only your smoke problem, but also the potential for carbon monoxide poisoning due to carbon monoxide being drawn back down the furnace chimney.