It also depends on how hot the roopm is.
If you have a 1000 watt bulb in a 4x4x7 closet (112 cubic feet)
A 285 CFM fan is not to much. Especiually if you hook the timer of to a thermostat switch. example - http://www.plantitearth.com/store/pr...id=133&catid=5


On a grand scale, you can use a 2000cfm exhaust fan on a 10x10x12 room (1200cubic feet). You should know, that when this fan turns on it will be difficult to open and close the door to your room.... very difficult... a fan like this will change thwhole dynamic of air flow in a house even a large house. Dust from chimmneys and crawl spaces can come into your house... yuck!!!!