you are going to be HATING it if you build that set-up with no AC. Even if your plants don't get roasted, they are going to stretch like fucking mad men. Some think that if you can't control temps you should just run co2. Co2 is awesome, and you can run hotter temps, but not that much hotter, especially in the last 2-3 weeks. You will loose allot of bud quality if it is above 80 during that time. I have 3600 AC hoods in a 12x9 room with a dehu and water cooled burner. my 12k mini split barely keeps up. It works great and I can get temps where I need them, but it runs constantly. I can also tell you, that unless you live in the desert or something; if you start running cold air (less than 40f) through your hood ducting, its going to start raining in your flower room with all the condensate because the warm moist air in your room will condense on the cold ducting. There is no way around that physics problem and I ahve tried ALL the solutions.