I use the window AC, if your going to use a specific AC for your grow I would get one of those portable one room AC's on wheels that has the 4" exhaust duct and window kit and vent the heat out the window. They make them pretty small so if you have the room put the until right in you room or tent with your plants(make sure the cold air isnt blowing directly on the plants) and use how ever many feet of aluminum dryer ducting you need to run out the tent and to a window. Also if your able and have a basement that stays 50f all year round you can use 4" or 6" duct, a fan, and pull cool air from a basement and you wont even need to run an AC. Or extra AC I mean. If you put an AC(portable) right in your grow tent(if that's what you have) I don't think you would even have to cool the room its in. My AC cools all 3 rooms upstairs so that's why I use it. No sense in running two, all this damn shit use enough power as it is.