The issue is where your makeup air is coming from. If your chimney is the source of (unplanned) makeup air, you can pull in exhaust fumes and kill yourself.
Correct.
This is not about electric brewing. Specifically without make-up, you risk
pulling CO gas from existing flu's, even further it is possible to pull sewer gas
from drains.
You should have make-up air, and have enough of it. Installing an 800CFM
fan and cracking a window are examples of what not to do..
I am all for Low cost, however do not compromise your health for low cost.
