the temperatures outside arent that hot here right now but when we do have those heat waves that 400 heats up the whole upstairs!! but in 12/12 i dont really stress over heat problems cuz it always has night to keep cool!! i do have a fan by the bottom of the bucket aimed up blowing on the plant and i leave it on 24/7 so at night cycle hoping it gets cold in there so my plant will purple.. but i looked at flo grows method of using a cooler & thats an awesome idea just duno about a lid cuz you wouldnt have to paint bucket to stop light from penetrating and it naturally keeps things cold might try that method within the next couple of grows!!