Bests & Worsts Reviews from Amazon

I've seen several posts about having problems with this product. It's been great for me, as long as I remember how it works. It works using natural convection, not a fan or a huge heat sink like a big block of ice. The fan you hear does not move air in the cooler. It only draws the heat out of the cooling element on the outside. The cooling element on the inside is just cold. Consider if you had a block of ice as small as a stick of butter in the corner of your cooler, that never melts. That is what this is like. There's no cool air circulating in the cooler, it's just sucking heat out from a small area. It will take some time, and if the area at the bottom of the cooling unit is blocked or insulated, the rest of the cooler will eventually get warm. I have a thermometer in an empty cooler that has been running for a couple of hours, and while the outside temperature is 72°F, the inside temperature is 28°F. Yes, below freezing. But if I place insulating items around the bottom of the cooling element, such as boxes of Thin Mints (so good!) then the rest of the cooler won't get nearly so cold. It can stay as hot as 50°F at the far end of the cooler when the cold can't be transferred there. So... as others have said, best place to start is with already-cold items. That will give the cooler its best shot. The next thing to consider is to place liquids and solids that transfer heat closer to the cooling element than boxes of loose items. Boxes that contain a lot of air will insulate the cooling element from the rest of the cooler. Allow as much airflow as possible around items. This will allow natural convection to mix the air as much as possible. (If you happen to have a mechanical engineer in the family who works with heat transfer devices or remembers his fluid dynamics from college, you're golden. :D ) One note: the cooler is not the most insulating thing in the world. It really does rely on the cooler to work for it to keep its temperature. If you keep it in the sun, it will get warm. Good luck! With some practice and planning, this thing will work as advertised, or better. I've had 50°F differences or greater between the outside and inside air.