how big of an exhaust fan do I need??

The dimentions of the room are 4ft X5 3/4ft and 8 ft high.
(with a 1000watt metal halide bulb)
we are wondering how big (CFM) the exhaust fan should be
Thanks to anyone who responds.

If its a 8inch diameter then them fans can get bigger , if your system uses 6in ducts n such, then just get the 450ish CFM, some of the biggest for that size, and you'll be set even with a 1000w HPS.

but you should also consider how far your trying to push the air, and if your pushing it far then even little booster (160) cfm fans along the way help a large bit and are a very cheap alternative then doubling the expensive more powerful ones.

what BBYY said ,
your choice 6 or 8 in inline fan will work ,
i think 8 is alittle over kill