I have a small 10' container above ground. It sits on two 8''x8''x10' beams which sit on bricks that are on a concrete pad. It is above ground obviously. I spray foamed the inside 3'' everywhere and framed it inside. I used 3'' hard Styrofoam for the floor then plywood. Where I am it gets to -30. This will be my first winter so I am working through everything still. I framed a door and also have an airlock style so I can get in, close the door behind me and then unzip the white plastic barrier to enter into the room. That way no cold gusts of wind will come through and kill my plants when I get in, since space is pretty tight. I have an 8x4 table inside and expect to pull 3-5 pounds per run. I would have gone with a larger container but it's not allowed where I am. I don't intend to run it during the summer as we are allowed 4 plants, but I do believe I could with the AC that is currently in there.....anyways it's all a learning curve right now. I have a crop on the go and it is starting to take off, will have to flip to bud soon. QB lights in the pic.