A faulty or leaking refrigerator door seal wastes energy. If the seal is dry and cracked, if you see condensation (water droplets) around the edge of it, or if your refrigerator is not staying as cold as it should, you may need a new seal. Leaks can also increase your energy bill and stress your refrigerator, shortening its life. They can also promote mold growth.
Check the door seal size. Measure your door or doors, and take down the make and model number.
Order a replacement door seal. It's easy to find them online. Make sure to check the model number for your refrigerator when you order it. When it arrives, hold the new door seal up against the old door seal to compare the size. The sizes are rarely incorrect, but it will save you the trouble of doing the job twice if you happened to receive the wrong door seal.
Locate the screws. Lift the edges of the seal and find the screws underneath that are holding in the plastic liner and door seal. Often, the screws hold in a plastic liner, which in turn clamps the door seal to the door.
Loosen the screws. Begin to loosen the screws that hold in the door seal. DO NOT take the screws all of the way out. It is unnecessary and will create more of a job for you. If at all possible, loosen only a few screws at a time, as you go.
Remove the old seal. Once all of the screws are loose, the door seal should easily slide out from behind the plastic liner. Don't be too forceful when doing this step, since some plastic liners can be quite brittle and crumble if you are too rough. If the plastic is old, replace it.
Insert the new seal. Begin slipping the small lip of the new door seal behind the plastic liner of the fridge. The best method is to start in the top corners and work your way around the door.
Tighten the screws. Once the door seal is in a certain section, you can begin tightening the screws. Begin with the 8 corner screws, and then check the alignment of the door while closed. Also check that the seal is even and straight. If the door is twisted, you can easily manipulate the door to twist back into shape whilst the screws are loose. Then tighten the remaining screws.
Apply powder. Use a bit of baby powder or talcum powder to prevent sticking. Rub some powder around the hinge side corners of the door seal, and where the seal slides. This will help to prevent the door seal from twisting as it meets the metal of the fridge. If this still doesn't prevent twisting, then wedge a screwdriver under the seal as you close the door and leave it shut for an hour.
Check for gaps. Look for any gaps in the door seal, especially at the top on the opening side. These can form due to the door dropping or being out of alignment. One way to check is to turn on a flashlight and place it inside, then close the door and look for light.
Fix any gaps in the door seal. Pack out the seal underneath the areas where the door seal has the gaps. This can be done with a small strip of weather stripping, as shown here, or a bit of tightly rolled up paper under the door seal. Alternatively, you can heat the door seal up with a hair dryer to fix the gaps. This softens the door seal and allows you to stretch it. Check the corners. If the application of powder hasn't prevented the door seal twisting, then wedge a screwdriver under the seal as you close the door and leave it shut for an hour. The door seal will then have enough time to mould into the correct shape.