I have my DIY cabinet set up with 2 bathroom exhaust fans. My first attempt I had problems and after reading more I understood approx CFM should be about 5X CF of incubator. I'm running 160CFM now. I have them set up a little different though. One 50cfm blows the hot air from the top heating compartment through ABS to the bottom of egg comp. the other 110CFM just blows straight down from the heating comp and I used the fan cover to diffuse the air.I've been thinking about making a cabinet style incubator. I'm trying to figure out what I can use and do it for cheap. Instead of the computer fans couldn't I use an old fridge fan? Or would that be too much air flow?