That's not nearly enough light for that space. What brand LED are you using? Check out my 4X8 room setup in my sig. I was using 3 MarsHydro TSW2000 and that wasn't enough, so I went for 2 TSW2000 and ordered a TSW3000 to replace one of them in the flower section. (It'll be here next week.) With that much space and an AC unit, you can do HPS or you're going to need a lot more LED light. Your space is 2X bigger than mine and you're planning on using 1/2 the light.
Do you have a drawing of how you want to lay everything out? Maybe we can take a look at that and opine on a better way to do it.
I'm still a newbie, but I've been really happy with growing autos. If you're doing a space that big, you can do what I'm doing and run a line. Crack 2-3 seeds every 2 weeks and have a perpetual grow going. you'll be harvesting 6-8oz every 2-3 weeks. Plenty to go around.
Good luck, and keep us all in the loop as to what you're doing. Lots of great people here that can help make the most of what you're doing.