My bathroom measures in at 289 cubic feet. Dividing that by 7.5 and rounding up gives me a target fan capacity of 40 CFM. However, there are many more fans available at 50 CFM.
I read this post, Are there drawbacks to installing a stronger bath fan?, stating that a fan moving more air than necessary can inhibit appliance fumes from venting properly, not the mention the HVAC efficiency hit from expelling conditioned air.
My question is this: will increasing from 40 to 50 CFM create such problems, or is that in the realm of a much bigger increase?
Best Answer
An extra 10 CFM won't hurt you at all.... If anything, it will get rid of the unwanted moisture faster. I'd wager that article was meant for much larger bathroom fans.