A frost free freezer means just that... frost free. In other words, you won't have the insanely tedious task of having to thaw your freezer to chip off all the frozen ice when you have trouble closing the door properly because of the frost build up.

With a frost free freezer, there are heating elements in the freezer walls that cycle through - normally every six hours but can vary depending on the make, model and energy effeciency - in order to melt any ice. There is a thermometer in the freezer so that it won't allow the freezer to get any warmer than freezing.

Now, a frost free freezer is very convenient however, it isn't as energy efficient as a manual defrost. A manual defrost will also ensure the temperature is steady rather than going through the heating and cooling cycles, which means that if you plan to store food in your freezer for months at a time, you may want to go with a manual defrost. But you will have to manually defrost every few months, something many people don't really like doing!

It is up to you to decide which type of freezer you prefer, as each have pros and cons.