A wooden front door is only as secure as the lock fitted to it. While timber doors are often strong and long-lasting, the wrong lock can leave your home vulnerable or fail to meet insurance requirements.

Choosing the right lock depends on the type of door, the level of security you want and whether the property needs to comply with your insurer's requirements.

BS3621 Mortice Locks

For most wooden front doors, a BS3621 5 Lever Mortice Deadlock is considered the gold standard.

These locks are independently tested and feature:

• Hardened anti-drill plates
• Strong deadbolts
• British Standard certification
• Increased resistance to attack

Many insurers specifically require a BS3621 lock on timber external doors. If you're unsure what your insurer expects, Are Your Door Locks Insurance Approved? explains the most common requirements.

Check for the Kitemark

Not all 5 lever locks are British Standard locks.

A genuine BS3621 lock will usually display the British Standard Kitemark on the faceplate and often on the packaging.

If your existing lock doesn't have the Kitemark, it may be worth upgrading.

Nightlatches

Many wooden front doors are fitted with a nightlatch, often known as a Yale lock.

A modern kite-marked nightlatch provides:

• Automatic locking when the door closes
• Convenient day-to-day use
• Additional security when combined with a mortice lock

For the best security, a nightlatch should be used alongside a BS3621 mortice lock rather than on its own.

Deadlocks vs Sashlocks

There are two common types of mortice lock.

Deadlock

• Operated by key only
• No handle operation
• Common on front doors alongside a nightlatch

Sashlock

• Includes both a latch and a deadbolt
• Operated by key and handle
• Common where a single lock is preferred

Choosing the right type depends on how your door is used and the level of convenience you want.

Insurance Requirements

Many insurance policies specify minimum lock standards for external timber doors.

Before replacing a lock, it's worth checking your policy requirements.

A BS3621 mortice lock is often accepted as meeting these standards, making it a popular choice for homeowners looking to improve both security and insurance compliance.

Door Condition Matters

Even the best lock won't perform properly if the door or frame is in poor condition.

Check for:

• Loose hinges
• Rotting timber
• Damaged keeps
• Loose frames
• Doors that don't close correctly

A lock is only as secure as the door it is fitted to. If your door is damaged, Repair vs Replace: What's Best for Your Door? explains when a repair is the better option.

Keyed Alike Options

If you have multiple timber doors, it may be possible to have locks keyed alike so one key operates several locks.

This can be useful for:

• Front doors
• Back doors
• Side entrances
• Garages

Reducing the number of keys you need to carry.

When Should You Upgrade?

Consider upgrading if:

• The lock is old or worn.
• You've moved house.
• Keys have been lost.
• The lock isn't BS3621 rated.
• The lock has been damaged.
• You want improved security.

Moving into a new property is one of the best times to replace external door locks, as you can never be certain how many keys are already in circulation. Why Change the Locks When Moving Into a New Home? explains why many homeowners choose to do this immediately after moving in.

Security and Convenience

For most wooden front doors, the ideal setup is a BS3621 5 Lever Mortice Deadlock combined with a quality kite-marked nightlatch. This provides excellent security, meets most insurance requirements and offers convenient day-to-day operation. If your existing locks are becoming stiff or showing signs of wear,– How Long Should a Door Lock Last? explains when it's worth repairing them and when replacement is the better long-term option.