[uranium]

Efficacy is also going to vary with usage. I've got a 900CFM fan, but I can still smoke up the kitchen pretty badly if I sear on the front burner, even with the fan on high. However, if I use the back burner, even with the fan on low, the air stays pretty clear.

[chasebank]

Are you sure it's really a 900CFM fan? A lot of cheap fans on amazon claim they are high CFM and when you look at components, are like 400 at best. High CFM fan will run you at least $2k to start.

[uranium]

It's a name-brand fan bought at a local showroom a decade ago. IIRC it was under $1000 at the time.