Freezer Frost Buildup?
8 Common Causes and How to Stop It

1. Door not closing all the way

Freezer frost is water vapor from room air that freezes the moment it touches a cold surface, and the biggest source is a door that stays open a crack. A package sticking out, a basket off its track or an upright that isn't tilted back enough to swing shut on its own all do it. Frequent opening adds more, and a garage freezer opened on a hot day takes in more moisture with every trip.

Can you fix it yourself? Yes.

1. Rearrange food and baskets so nothing touches the door.
2. Adjust the front leveling legs so an upright tilts slightly back and swings shut when released.
3. Get what you need in one trip and close the door right away.

2. Worn or dirty door gasket

The freezer door gasket is the rubber seal around the door, and when it cracks, flattens, pulls out of its channel or gets coated in sticky residue, humid air leaks in around it all day. The frost shows up as a band just inside the door opening. Test the gasket rather than judging it by eye: the corners usually leak first.

Can you fix it yourself? Often, yes.

1. Clean the gasket and the cabinet face with warm, soapy water and dry them.
2. Close the door on a dollar bill at several points and pull it out.
3. If it slides out easily, order a replacement gasket by model number.

A door that sags on its hinges needs the hinge adjusted first, or a new gasket won't seal either.

3. A manual-defrost freezer that's due Manual defrost

Some upright freezers have no automatic defrost, so frost on their walls is normal and builds until you defrost by hand. Whirlpool's defrosting guidance (opens in a new tab) is to defrost when the frost reaches about 1/4 inch, at least once a year, and more often in humid areas. Past that point, frost crowds out storage space and makes the freezer work harder. A drain plug left out after the last defrost lets air in, and the frost comes back fast.

Can you fix it yourself? Yes, and it's a routine job.

1. Move the food into coolers or another freezer, then unplug the freezer.
2. Open the drain and set a pan under it, or lay towels around the base.
3. Leave the door open and set bowls of hot water inside to speed the melt.
4. Loosen softened frost with a plastic or wooden spatula, never a knife.
5. Clean and dry the inside, close the drain and plug it back in before restocking.

4. Warm, wet or loosely wrapped food

Warm, wet or loosely wrapped food brings its own moisture into the freezer. Leftovers that go in steaming, produce still wet from washing and bags with air trapped inside all give off water vapor, which settles as frost on the walls and inside the packages. That's also where freezer burn comes from: food that loses moisture to the air around it dries out in grayish, leathery spots.

Can you fix it yourself? Yes, entirely.

1. Let cooked food cool before freezing it, or chill it in the fridge first.
2. Use airtight containers or freezer bags and press the air out before sealing.
3. Dry washed produce before it goes in.

5. Ice maker or dispenser letting water or air in Ice maker

In the freezer section of a refrigerator with an ice maker, two small faults cause a lot of ice. A water valve that doesn't close fully drips into the ice maker and builds lumps of ice around the mold, the fill tube and the bin. On models with ice through the door, a cube stuck in the dispenser flap holds it open, so warm air streams in and frost forms around the chute.

Can you fix it yourself? Partly. Clearing a stuck cube from the dispenser flap is easy. A dripping water valve or a frozen fill tube is a repair; our guide to ice maker not making ice covers the rest of the ice maker.

6. Clogged or frozen defrost drain Frost-free

When a frost-free freezer defrosts, the melt water runs down a trough under the evaporator coil and out through a drain tube to a pan underneath, where it evaporates. If food debris clogs that drain or the water freezes in it, the water has nowhere to go. It refreezes as a flat sheet of ice on the freezer floor or under the back panel, and in a refrigerator it can overflow into the fresh-food side or onto the kitchen floor.

Can you fix it yourself? Sometimes. If the drain opening is in plain sight, unplug the freezer and flush it with warm water from a turkey baster. A drain hidden behind the back panel is a technician job, and one that keeps freezing usually means the heater that keeps it clear has failed. For water on the floor, see refrigerator leaking water.

7. Burned-out defrost heater Frost-free

A frost-free freezer has a defrost heater on the evaporator coil behind the back panel, and when it burns out nothing melts the frost. On a schedule, the control shuts the compressor off and runs the heater to clear the coil; without it, the coil disappears under snow-like frost that spreads across the back panel. Airflow drops, the freezer warms, and in a refrigerator the fresh-food side warms with it. If food has started to soften, see freezer not freezing.

Can you fix it yourself? Partly. A full manual defrost confirms the pattern if frost returns within days, but testing the heater means removing the back panel and checking it with a meter, which is a job for a technician.

8. Defrost thermostat, timer or control board Frost-free

A freezer's defrost heater only runs when two other parts let it. The defrost thermostat, a small sensor clipped to the coil, lets the heater run while the coil is cold and switches it off once the frost is gone. The defrost timer or control board decides when a defrost cycle starts. If the thermostat fails or the timer stops advancing, the heater never runs and the frost builds exactly as it does with a dead heater.

Can you fix it yourself? No. Telling a failed thermostat from a failed timer or board takes meter readings at the right point in the cycle, and replacing the wrong part fixes nothing.