Unfortunately many manufacturers show the airflow rating only measured straight from the motor. I have seen even Miele and Sebo doing this and claiming huge cfm figures. Sounds good, but it's far from the real cfm.
158 CFM. Really?
http://www.ristenbatt.com/xcart/Miele-S8590-Alize-S8-Canister-Vacuum-Cleaner-Specifications.html
158 CFM. Really?
http://www.ristenbatt.com/xcart/Miele-S8590-Alize-S8-Canister-Vacuum-Cleaner-Specifications.html