I was busy putting up that clear shrink-film window covering all around, and decided to cover the opening to my fireplace. WOW! I just couldn't believe how much air was flowing up / down that chimney, even though the damper was shut tightly.
It's a typical main fireplace, about 4' x 5'. Once sealed, the film acts almost like a large human lung sometimes! It's windy here in the Chicago area today, and at times I was wondering if the double - stick tape was strong enough to hold the film from pulling in and out.
I've read about inflatable chimney blocks. Has anyone used one, and if so, does it do the job?
This is amazing. I don't think it's my imagination that the rest of the house seems warmer, since there's so much less air infiltration, even around windows that I haven't sealed with film. This is an otherwise well-built home, but I guess that an air-tight fireplace seal wasn't important in the early 1940's...