Unlike manual defrost freezers that build up ice, frost-free freezers automatically remove frost so that ice does not accumulate. Manual-defrost freezers require users to unplug the freezer, empty the freezer contents, place bowls of boiled water inside the freezer to defrost the ice and lay towels at the base of the freezer to absorb the melted ice. Although frost-free freezers do not require as much maintenance, these freezers have their own set of problems.
Frost-free freezers generally cost more to purchase than manual defrost freezers. In addition, frost-free freezers use more energy to run, which translates to long-term higher costs.
Modern frost-free freezers depend on complicated internal mechanisms, such as a heating element, timer and sensors to perform the automatic defrost. Repair problems can arise if any of these parts falter. Manual-defrost freezers tend to need less repairs because of their simpler design.
For frost-free freezers to defrost properly, air must circulate between the food contents. Consumers must follow manufacturer's instructions when storing food in frost-free freezers to ensure that the freezer is not overstuffed and subsequently not defrosting properly. Manual-defrost freezers do not have the same storage restrictions.
Automatic-defrost freezers tend to make more noise than their manual-defrost counterparts. While those who store freezers in a garage or basement may not care about the noise, consumers who store the freezer in the kitchen or dining room may find this annoying.
The automatic defrost cycle in frost-free freezers can cause a freezer-burn taste in frozen foods. As the defrost cycle runs, the foods change temperatures which causes the freezer-burn taste. Freezer-burn not only tastes bad but can also cover up signs of food spoilage, making the food dangerous to eat in some cases.
Manual-defrost freezers require users to empty freezer contents periodically, which forces users to sort through stored items and find foods that are approaching their expiration dates. Many people who have frost-free freezers do not reorganise their freezers often enough. They sometimes forget about items in the back of the freezer and just use contents they can find easily, which causes monetary loss as foods in the back of the freezer can spoil before they are eaten.