DIY paint booth fan question

I have a 2 car garrage that i do my paint and body work in. I have a window in the back wall and a passage door with a storm door that i open the window on it. The window on the back wall I use old Rheem heaters, blower assembly mounted to the window frame. Wet the floor before painting and i don't get dirt in my paint. Been doing this for the past 7 or 8 years with great results.