I'm governed by my kennel size ,which is 7ftx 7ft so I can't have a very large box as it will take up too much room ,the boxes are going to be 2.5 ft cubes,..they are in 3 ft boxes at the minute,so I'm just creating a little bit more space whilst having the boxes up off the ground....I've had a bulb blow on me one time so I prefer the tubes,and miles cheaper to run