How big can you really go??

Iv been growing for about a year and a half now and have had some succes my first few harvest were not to abuntant but after my first 3 it real started to take off i had the strain super silver haze fall into my lap so i cloned the hell out of it. It went from 15 plants under a 400w hps to 50 plants under a 1000w with some serious resin trichomes definetly heady then i learn how to dry and cure correctly and ever since then its been bomb bud for the last 3 harvest. I want to go bigger, and move my grow room into the master bedroom its about 20 by 15 feet an right now i have a 1000w and a 400w will that be enough lite for that space maxed out, if not how much more do u think ill need?? and with a grow room that size with a carbon filter 75 is another 1000w to much?? so i guess how big can u really go but being safe ya know????

You will definitly need more lights, but im terrible with math and cant think of the how much you would need.