I couldn't find anything in International Residential Code that specifies range hood size, so it would appear that size is more of a style choice. Table M1507.4 does say that the minimum exhaust rate of the hood must be 100 CFM intermittent, or 25 CFM continuous.

I couldn't find anything in International Residential Code that specifies range hood size, so it would appear that size is more of a style choice. Table M1507.4 does say that the minimum exhaust rate of the hood must be 100 CFM intermittent, or 25 CFM continuous.

Section M1503.4 of the IRC says that if the exhaust hood exhausts 400 CFM or more, then you must provide makeup air at the same rate. It also says that the makeup air system shall provide a means of closure, and must automatically and simultaneously operate with the exhaust system.