http://www.greatlakeshomeperformance.com This video is aimed at home performance professionals. Demonstration of the Energy Conservatory Flow Meter (box) to measure bath fan flow in CFM for code compliance and other home performance testing. The meter and gauge can be purchased at the following link: http://www.energyconservatory.com/pro...
I recommend buying directly from them instead of the few dealers or Amazon that may be resellers. Keep in mind that certified raters get a 10% discount off their orders there.