I live in a townhouse and I hired a company to remove the smoke odor in the house. Now, the odor is almost gone when the heat is off.
However, every time I turn on the heat, the smoke odor will come back. The company I hired says the odor comes from my neighbor. They tell me that, because there is smoke smell in my neighbor's house (which is true) and our ventilation systems are connected (which I am not sure), the odor will be sucked into the vents and then get into my house when I turn on the heat.
But my furnace is a closet in my living room, and my neighbor's heat is NOT on when I turn on my heat. That's why I'm not sure if the ventilation systems are connected.
So I wonder if there is a way to tell if my ventilation system is connected to my neighbor's.
Also, if it's connected, how to fix it? If it's not connected, what could be the cause of the odor when the heat is on?
Thank you very much!