When you open up your freezer, it should feel cold. However, it should not look cold. Your freezer should not be full of frost.
Opening & Closing Your Freezer Door
There may be a buildup of frost inside your freezer for a couple of different reasons. To start with, if you open and close your freezer a lot, the buildup of frost may be because of you. Every time you open and close your freezer door, you are letting in warm air that may also be humid air. The air that you let into your freezer may freeze right away on your evaporator coils.
If you frequently open your freezer door, or leave it open for extended periods of time, all you need to do to stop the buildup of frost inside your freezer door is change the way that you use your freezer. If you spend a lot of time with your freezer door open because you can't find what you are looking for, you should reorganize the items in your freezer so you can quickly grab what you need and close the door.
Damaged Door Gasket
The second reason that frost may be building up in your freezer is because the gasket around your freezer door is damaged. The gasket is that black squishy material that runs around the edge of your freezer door. It acts as a seal and compresses when you shut your freezer door, keeping the warm air out.
Open your freezer door and insert the gasket. If you find any cracks in it or if it is brittle at all, you are going to need to replace it. To replace your gasket, just purchase a replacement at your local hardware store. You can pry the gasket out of your freezer door; you may want to use a screwdriver to get the gasket out. When you remove the gasket, wipe down the area where the gasket was located, then push the new gasket into place. If the gasket is too long, you may need to cut it down to size.
The third reason that your freezer may be full of frost is because of a damaged compressor. Most modern freezers are designed to self-defrost. In order to self-defrost, the compressor in your freezer turns on a couple times a day and melts any frost that has built up on the coils, which then drains out into your unit's drip pan.
You can turn your compressor off for a day or so and then turn it back on in an attempt to reset your compressor. You can also have a appliance repair technician, like one from Pro-Tech Equipment Service, come out to your home and fix your compressor.