I have a 10x18 insulated shed. currently running a 2x4 T5 and 1 600w HPS and several fans.
I may add a 1k light but that is not set in stone yet.
A 5k unit may do the room as is, add the about 1k watts of light and fans i have a 9k unit
may be warranted then allowing for future additions maybe a 12K would be the way to go.
So in planning i know i may want a little more but how do you decide when there are too many BTUs?
my 12000btu inverter can handle my 3k of lights, co2 generator, ballasts in room, and dehumidifier. but it wouldnt handle much more than that, i can keep room at 80 with lights on but it stays on the whole time.