Well I have been having the same problem lately. Trying to set up my veg box. However I read a few different sources that say 250w run about the same temp as 400w (with in 5 deg of each other) I would say if you have heat problems go for the 250w but if heat is not your biggest problem go for a 400w in a 6"cool tube running at least a 265cfm fan and that would be great for your area. or possibly a 250w with a light mover and a ScrOG set up. That might be the shit