I am trying to size my bathroom exhaust fan. Most sizing chart says to use the SQFT size and multiply by 1.1 to get the CFM if ceiling is standard 8'. So for a 10x10 bath = 100 SF it would be 110 CFM.
However when you use finish using your bath typically you have the fan on and the bathroom door open right? So it's drawing the air in the bath PLUS the air from outside the bath. Would it be a good rule of thumb to overshoot the 1.1 multiplier? or that already have a safety factor built-in?
Thanks,
MC