As was discussed briefly before, some of these units can remain cool even while they are not being powered. When it comes down to it, it is all about the power of insulation. With a normal ice cooler that is not designed to be powered via an electric power source, they only work as well as their interior insulation does. But, the thing about insulation is it is going to slow down the heat transfer but it is not going to stop it. There is no stopping this so when it is not running, ensure that you leave the lid closed as much as possible and only open it when you need to (and do it fast). Allowing the cold air to escape will speed up the heating process, much like in a normal refrigerator when your power goes out.