Why Winter Causes Lock Problems – And How To Prevent Them

AMZ Locksmith – West & North West London

As temperatures drop in London, homeowners start to notice new issues with their doors, locks, and handles. Winter is one of the main reasons for sudden lock failures, stiff handles, jammed cylinders, or multipoint systems that refuse to engage.

Cold weather affects both wooden and UPVC doors in different ways. Understanding these problems early can save you money and prevent emergency lockouts.

Below are the most common winter lock issues and how to avoid them.

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1. UPVC Doors Contract in the Cold

UPVC naturally shrinks in low temperatures, even by a few millimetres.

This small movement is enough to cause:

Difficulty lifting the handle

Gearbox not engaging the hooks or bolts

Misalignment with the frame

Door rubbing on the latch or striking plate

When the door moves, the multipoint system becomes strained. Over time, this stress causes the gearbox to fail.

Solution:

A simple door realignment usually fixes the issue. This takes pressure off the mechanism and prevents expensive failures.

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2. Gearboxes Break More Often in Winter

Cold temperatures make lubricants thicker, metal parts contract, and the mechanism stiffens.

When a customer forces the handle, the gearbox often snaps internally.

Signs your gearbox is failing:

Handle won’t lift fully

Key turns but the door won’t lock

A crunching or grinding sound

Lock works only when the door is open

Handle goes floppy or loose

If you notice any of these signs, it’s cheaper to replace the gearbox early rather than waiting until it breaks completely.

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3. Wooden Doors Swell and Stick

Wood reacts opposite to UPVC.

In the winter, moisture causes wooden doors to expand, making them difficult to close or lock.

Common symptoms:

Key gets stuck

Lock is hard to turn

Door must be pushed or lifted to lock

A swollen door puts extra strain on the mortice lock or nightlatch, often causing a failure.

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4. Cylinders Freeze or Become Stiff

Frost, moisture, and condensation can enter the cylinder, making the key difficult to turn.

This is common in:

Euro cylinders on UPVC doors

Rim cylinders on wooden doors

External garage and shed doors

Cold weather also causes oil inside the cylinder to thicken or dry out.

Solution:

Use a dry Teflon spray, not WD-40.

WD-40 attracts dust and can damage modern cylinders.

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5. Handles Feel Hard to Lift

In winter, the entire multipoint strip becomes stiff.

The linkage bars, hooks, rollers and deadbolts lose lubrication or contract slightly.

Forcing the handle is the number one reason gearboxes break in December–February.

If the door only locks when open, it’s misaligned and needs adjustment.

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6. Nightlatches Fail More Often in the Cold

Nightlatches (Yale-style locks) can suffer from:

Sticking latches

Loose internal springs

Spindle movement

Metal contraction causing the latch not to retract fully

These issues are subtle but can make doors impossible to lock when temperatures drop.

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How to Prevent Winter Lock Problems

Here are simple steps homeowners should follow:

1. Keep the door aligned and closing smoothly

2. Lubricate the cylinder with Teflon spray every 3–4 months

3. Never force the handle if it feels heavy

4. Get a professional to check the gearbox if the door only locks when open

5. Replace worn cylinders before winter

6. Ensure the door isn’t sagging or rubbing

A £65–£85 alignment can prevent a £150–£250 gearbox replacement.

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Professional Winter Lock Repair – AMZ Locksmith

AMZ Locksmith provides:

UPVC door realignment

Multipoint gearbox replacement

Cylinder upgrades

Nightlatch and mortice lock repairs

Emergency lockouts

Winter door and lock servicing

We cover West London, North West London, and surrounding areas including Acton, Harlesden, Willesden, Wembley, Shepherd’s Bush, Chiswick, Maida Vale, and Queen’s Park.

If your lock feels stiff or your handle is harder to lift in the cold, it’s best to fix it early.

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