Rule of thumb: 5,000 Lumens per sqft in flower.
4'x4'= 16sqft x 5,000L = 80,000 Lumens for optimal flowering.

Most 600w HPS bulbs put out around 88,000-90,000Lumens.
Didnt find an 800w, but 750w puts out around 110,000L.
SmokeMyPiece Reviewed by SmokeMyPiece on . 4X4 room, I was told I need 800 watts? Is that right. I've been doing some browsing online and found some websites that suggest that my room (4X4X8) would require a minimum of 800 watts HPS/MH lighting setup. Do you think thats right? I can get a lighting system that includes everything for $250.00. Is that price, high or low... Any help is greatly appreciated. Rating: 5