Depending on the hood you could probably get away with 1 1000, i.e. spend more on your setup. I have 2 400s and wish I would have spent a little more bc 1 1000 will pull less electricity then 2 600s or 400s for that matter bc its not just about the bulbs usage but also the ballast usage. Its what ever you want to do but I have had probelms with blowing breakers in my bathrooms with 2, which can also mess up your cycle, word of warning!