While most refrigerators, freezers, and refrigerator-freezers on the market today have automatic defrost controls, some models are available with manual defrost.
Automatic defrost refrigerators work by heating the interior refrigerator coils at regular intervals. This prevents frost from building up and allows for effective cooling of the refrigerator or freezer. However, because it introduces a heating element to the cooled space, the refrigerator uses more energy than it otherwise would.
By contrast, a manual defrost does not contain automatic heating elements. While this reduces overall energy use, it requires the owner to defrost the coils manually. This is because as frost builds up on the coils, airflow is restricted, and the coils will not cool as efficiently. The frost comes from the moisture out of the air that enters the freezer when you open the door, and from moisture out of food. Too much frost can prevent the door from closing properly and cause other damage. Proper maintenance is necessary to realize the energy savings of manual defrost refrigerators. A general rule of thumb is to not allow frost to build up more than one-quarter of an inch.
Defrosting should only be done when, and as soon as, necessary. The amount of time in between defrosts varies as to how often the door is opened and depends on the relative humidity in your kitchen.
Because the defrost process can take several hours, it is best to plan ahead because you will need to take everything out of your refrigerator and freezer. Anything that needs to be kept cool during the defrost should be put in a cooler with ice. To manually defrost your refrigerator and freezer:
- Take everything out of both the refrigerator and freezer and turn it off.
- Open all the doors to allow warm air to circulate inside.
- Place towels at the bottom of the compartments to collect and absorb the liquid as it melts.
- Once the machine is completely defrosted, clean the inside with soap and water.
- After washing, rinse the inside with non-soapy water to remove soap residue, wipe with dry towels, and allow to air dry for at least an hour. It is important that the refrigerator be clean and dry before turning back on. Once it is completely dry, return any food to the refrigerator and turn it back on to the appropriate temperature setting.
- DO NOT chip, scrape, or pry at the frost build-up.
- DO NOT use heat sources such as a blow dryer, they can damage the plastic interior of the refrigerator and/or present a shock hazard.
As always, if you have any questions regarding the proper care of your refrigerator or freezer, refer to your owner's manual or contact the manufacturer. Manufacturers recommendations always take precedence over general rules of thumb.