Hi, guys! (I created the same thread in the Engineering topic nearly a week ago but there has been no response. So I decided to move it here. Thanks.) A few friends and I just had a discussion regarding heat and cold protection in general. Then came across a question of whether it is more difficult and energy consuming for heat protection or for cold protection, or is it the same. Let's take an example. We have a void cube (with air inside) of a certain peripheral insulation material. Let's say that we somehow adjust the inside temperature of the cube at 10 degrees Celsius and put the cube in a constant air (same type of air as in the cube) environment of 30 degrees Celsius and after 1 hour the temperature inside the cube is 15 degrees Celsius. The question is: if we adjust the inside temperature of the cube at 20 degrees Celsius and put the cube in a constant air (same type of air as in the cube) environment of 0 degree Celsius, what is the temperature inside the cube after 1 hour? Would it be 15 degress Celsius? or higher? or lower? I would really appreciate the answer and full back up knowledge for that. Thanks a lot!