I checked the specs on the Hayden fans and the 16" fan 3700 has 1400 cfm, the 16" model 3710 fan is 1500 cfm and the 12" model 3680 is 800 cfm. They also the Dual 12" Fan model 3800, which I have, has 1600 cfm which is better than either of the 16" fans. So at least with hayden, they claim two 12" is better than one 16".

Wayne