Standard size range vent hoods are available from 24 to 60 inches with size steps in 6-inch increments. Typically it is recommended that the correct hood vent size is at least 3 inches larger in each direction than the range top.
The size of the vent hood needed on an electric stove directly correlates to the size of the fan, and duct, required to effectively filter out the volume of pollutants produce by the range. Fan size is measured in cubic feet per minute. Generally 100 CFM is needed for every 10 inches of stove width. The duct size required is directly proportional to the CFM generated by the fan. Duct size for 0 to 600 CFM fans should be 8 inches minimum with 601 to 1200 CFM fans recommended for a 10-inch minimum duct.