if your only growing for personal use you probably do not need a 4 by 4 area or a 1000 watt light its would be a big jump to go from what you have now to just a hid depednding on how much you want to yield, your flower room size should match your light and shoot for 50 watts per sq ft of hid lighting, if you are just growing for personal use, a 400 in a 2 by 4 area or other size that equaled 8 square ft should supply most people if they are cloning and using mother plants to there advantage.