You mentioned its cheaper (electricity wise) with the T5s but you also said its 400 watts...and watts is watts when it comes to the bill so it should be the same. Also how many lumen's does each bulb put out....I have a veg/clone setup with about 6200 lumen's, 3100 per bulb. I decided to use that in lieu of my MH and flower them under my 400 Watt HPS.