If you own a freezer, whether that be an upright or chest freezer, you may be wondering why the exterior walls and the top seem to be hot. A freezer that is hot to the touch on the sides and top is a good thing. In fact that heat means that the freezer is working properly. Let me explain.
Most refrigerators today use a condenser to remove the heat from the refrigerant that is located in the base of the refrigerator behind the grill near the compressor. A fan blows across the condenser which is a group of coils with fins on them to allow the heat to be drawn off of the refrigerant and put back into the room. This allows the refrigerator to keep your beer cold.
Because freezer walls are so thin, freezer manufactures needed to figure out a way to prevent the cold air inside the freezer from effecting the exterior walls. If the exterior walls got cold moisture would form on them causing the freezer cabinet to rust. You may have noticed that when you have a glass with ice in it moisture condenses around the outside of the glass. That’s because the ice in the glass makes the exterior part of the glass so cold that the moisture around it condenses from a gas that we know as humidity, to a liquid. The liquid water then runs down the side of the glass. Mostly that’s why we need coasters.
If the cold air inside a freezer was allowed to affect the outside walls and top of a freezer you would have moisture all over the exterior walls and top. In fact in hot humid areas such as Florida, you would actually have puddles of water around your freezer and eventually the freezer walls would start to rust.
To prevent this from happening freezer manufactures take the condenser that would normally be under the freezer and run that tubing inside the exterior walls and top. This allows the walls to heat up preventing moisture from condensing on them. There is a layer of insulation between this tubing and the inside walls and top of the freezer. This concentrates the heat from the condenser tubing on the outside walls and top and prevents it from migrating back into the freezer.
So if your freezer walls are very hot to the touch, the freezer is doing it’s job properly. And one last thought on the subject. I’ve seen lots of freezers mostly located in garages, that have a bunch of junk piled on top of them. Although the top of the freezer is a convenient place to store stuff, it actually diminishes the freezer’s ability to do it’s job by insulating the top of the freezer preventing it from allowing the heat to go back into the room. If you must put stuff on the top of your freezer, put a couple of 2 x 2’s front to back on the top of the freezer with a three-quarter inch piece of plywood on them to make a shelf. This will allow air to flow under the plywood allowing the freezer to give off heat. Doing so will likely prolong the life of the freezer.