well, if the sun is directly above the tube, it would get maximum sunlight. the other times of day, it will be at an angle to the pipe, forcing the light to bounce back n forth down the tube, and in turn will be less intense. another problem may be light from the closet going back up the tube. you could just cap it at night i guessYup exactly they have the super reflective pipe and fittings. Gets the lights from the roof so you got peak light all day everyday.