Door lock frozen and the key won't go in? How to thaw it without breaking it

The lock worked yesterday. This morning the key will not go in, or it goes in and will not turn. If the night dropped below freezing, the most likely cause is ice inside the cylinder. Moisture gets in from rain, sleet, melting snow, or even condensation, and when it freezes it locks the pins in place.

Ice is usually easy to clear. The damage comes from what people do in a hurry: forcing the key, pouring hot water, or putting a flame to the lock. This guide covers home and business door locks only. Roger does not handle vehicles of any kind.

First: do not force the key

A key that meets ice is pushing against pins that cannot move. Turn hard and the key can bend or snap off inside the cylinder. A broken key in a frozen lock is a much bigger job than ice. If the key does not go in or turn with normal hand pressure, stop and thaw the lock first.

How to tell it is ice

• It started on a cold morning, after rain, sleet, or snowmelt the day before.
• The lock has been fine until now, and your key works in other locks.
• You can see frost or water around the keyhole, or the face of the lock is iced over.
• The door faces the weather, or water drips onto the lock from above.
• If the key also sticks on warm days, ice is not the whole story. The lock or the key is worn, and the cold just made it worse.

Safe ways to thaw it

• Warm the key in your hand or pocket for a minute, then insert it gently and let it sit. Repeat a few times. A warm key melts a thin layer of ice.
• Use a lock de-icer made for door locks. It is mostly alcohol and melts ice fast. Spray a short burst into the keyway, wait, then try the key gently.
• Warm the lock face with a hair dryer on a low setting, held a short distance away. Use it only where the cord, the outlet, and your hands stay dry, and never on a wet or snowy step with the cord in water.
• Hold a hand warmer pack against the face of the lock for a few minutes if you have one.
• Once it turns, work the key in and out and turn it a few times so the pins move freely while the lock is still warm.

What not to do

• Do not pour hot water on the lock. It melts the ice for a moment, then runs deeper into the cylinder and refreezes harder.
• Do not heat the key or the lock with a lighter, torch, or any open flame. It can burn you, scorch the door and its finish, damage weatherstripping, and ruin the electronics in a keypad or smart lock.
• Do not hit the lock or pry at the door. A cold lock body and a cold door frame crack more easily.
• Do not spray an oily lubricant into the keyway. Oil thickens in the cold and holds water and grit, which makes the next freeze worse.

Keep it from freezing again

• After it thaws and dries, put a puff of dry graphite or PTFE lock lubricant in the cylinder. It pushes out moisture and keeps the pins moving.
• Look for where the water comes from. A missing gutter, a drip from the trim above the door, or snow piling against the door all feed the lock.
• A keyhole cover or a small weather shield over the lock keeps rain and sleet out on exposed doors.
• Smart locks and keypads lose battery power faster in the cold. Change the batteries before winter, and know where your backup key is.

When a locksmith is the better call

Call a locksmith if the key snapped off in the lock, if the lock still will not turn after it is clearly thawed, or if it freezes every time the temperature drops. A lock that keeps freezing usually has water getting in through a worn or poorly sealed cylinder, and a locksmith can clean and service it, rekey it, or replace the cylinder with one better suited to an exposed door.

If you are locked out in the cold and nothing has worked, a locksmith can usually open the door without drilling and then deal with the frozen lock once you are inside.

What moves the price is whether it is a lockout, whether a broken key has to be extracted, whether the lock can be serviced or the cylinder has to be replaced, how many locks are involved, and the time of day. You see a qualitative range up front, and the locksmith confirms the price in person after seeing the lock.

Booking through Roger

Describe the problem: which door, what the key does, whether this happened after a freeze, and whether you are locked out or just cannot lock up. Roger books one vetted local locksmith and confirms the appointment, so you know which company is coming. Home and business only.

You can describe the problem on rogerrepair.com and get one locksmith booked.