A Guide on How to Choose the Best Locks for Your Doors

Why Your Choice of Lock Matters

Your door locks are your first and most important line of defence against unauthorised entry. A high-quality, correctly installed lock can make the difference between a secure property and a vulnerable one. Equally, fitting the wrong lock type - or a poorly made one - can give a false sense of security without providing meaningful protection.

This guide will help you understand the main types of door locks and how to choose the right one for each door in your home.

Factors to Consider When Choosing a Door Lock

Purpose of the Door

External doors - front doors, back doors, side gates - require a much higher level of security than interior doors. For interior doors such as bedrooms, bathrooms, or storage rooms, convenience and privacy typically take priority over security strength.

Door Material and Construction

The material and thickness of your door affects which locks can be fitted. Wooden doors, metal doors, and uPVC doors each have different characteristics:

• Wooden doors suit mortice locks and cylinder deadbolts well
• uPVC doors are almost always fitted with euro cylinder locks and multi-point locking systems
• Metal and composite doors may require specialist hardware

Always check the manufacturer’s guidance and, if in doubt, ask a local locksmith.

Budget

Security should not be compromised for cost, but it is possible to find good-quality, certified locks at a range of price points. Spending a little more on your main entry locks is a sound investment.

Common Types of Door Locks

Deadbolts

Deadbolts are among the most secure options for external doors. They use a solid metal bolt that extends deep into the door frame, making them very resistant to forced entry. They come in two main variants:

• Single cylinder: key outside, thumb turn inside - the most common choice for residential front doors
• Double cylinder: key required on both sides - useful where there is glass near the door, but presents a fire safety consideration

Mortice Locks

Found in many older UK properties and commonly used in commercial buildings. Mortice locks are recessed into the door edge rather than surface-mounted, which makes them strong and resistant to tampering. They typically combine a latch and a deadbolt in a single unit.

Euro Cylinder Locks

The standard lock on most uPVC doors. The cylinder is a replaceable insert that controls the locking mechanism. Their main weakness is vulnerability to cylinder snapping - a common burglary technique. Always choose anti-snap cylinders for any external door.

Night Latches and Rim Locks

Night latches (often called Yale locks) are surface-mounted on the inside of the door. They provide convenience - the door locks behind you when you leave - but should never be your only lock. Always pair a night latch with a mortice deadlock. Choose a model with a deadlocking function that prevents the latch from being pushed back with a card or thin tool.

Knob and Lever Handle Locks

Suitable only for interior doors. These locks can be defeated with basic tools and should never be used as the sole lock on an external door.

Security Ratings: What to Look For

BSI Standards

The British Standards Institution tests and certifies locks against recognised performance standards. For home insurance compliance and genuine security, look for:

• BS 3621 - the standard benchmark for deadlocks
• BS 8621 - for key-operated deadlocking night latches
• BS 10621 - for double-locking latches

Sold Secure Ratings

An independent testing scheme with three rating levels:

• Bronze - entry-level security
• Silver - medium security
• Gold - maximum tested resistance

For external doors in residential properties, aim for at least Silver, and ideally Gold on your main entry point.

Smart Locks: A Modern Option

Smart locks offer keyless entry via a smartphone app, PIN code, or fingerprint. They can be monitored remotely, set to allow temporary access, and integrated with other smart home devices. For a full comparison of smart lock types and models, see our guide to smart locks for a keyless home. However, they should complement a quality mechanical lock rather than replace it entirely - most smart locks are not yet tested to the same standards as mechanical alternatives.

Lock Maintenance

Even the best lock will deteriorate without basic care:

• Apply a graphite-based or silicone lubricant to the keyway every six to twelve months
• Check screws and fixings for looseness annually
• Replace cylinders that show signs of wear before they fail

For help identifying when a lock is failing, see our article on 5 signs of a broken door lock.

Tips for Better Home Security

Beyond choosing the right locks, several simple habits and additions can significantly improve your home’s security:

1. Upgrade old locks - If your locks are over 10 years old, the internal mechanisms may be worn and easier to manipulate. A professional lock change is quick and affordable.
2. Use multi-point locking - Multi-point systems engage three to five locking points along the door edge, making forced entry far more difficult than a single-point lock.
3. Never hide spare keys - Under doormats, in flower pots, and above door frames are the first places burglars check. If you need emergency access, leave a spare key with a trusted neighbour instead.
4. Install a door chain or limiter - A chain allows you to open the door partially to identify visitors without exposing yourself. Door limiters serve the same purpose with a more modern design.
5. Secure your windows - Window locks are just as important as door locks. Ground-floor and accessible windows should have key-operated locks.
6. Fit a door viewer - A wide-angle peephole lets you see who is at the door without opening it. This is especially important for vulnerable residents.
7. Use timer switches on lights - When you are away, automatic lights create the impression that someone is home. Smart plugs make this simple to set up.
8. Trim hedges near entry points - Overgrown hedges provide cover for burglars working on your door or windows. Keep the area around your front door clear and well-lit.

When to Call a Professional Locksmith

If you are unsure about your home security, a professional locksmith can assess your property and recommend the best solutions. Common reasons to call include:

• Moving into a new property - You have no way of knowing who has copies of the existing keys. Changing the locks is the only way to be certain.
• After a break-in or attempted break-in - Compromised locks must be replaced immediately to prevent repeat incidents. Our break-in repair service responds within 25 minutes.
• Lost or stolen keys - If your keys have gone missing, anyone who finds them could potentially access your home.
• Visible wear on existing locks - Stiff operation, loose fittings, or visible rust are signs that your lock is no longer providing adequate protection.
• Insurance requirements - Your insurer may specify certain lock types. A locksmith can check compliance and upgrade where needed.

At City Locksmith London, we offer free security assessments and competitive prices on all residential locksmith services. Our locksmiths carry a full range of high-security locks in their vans, so most upgrades are completed in a single visit.

Get the Right Lock Fitted Properly

Choosing the right lock is only half the job - a poorly installed lock provides far less security than its ratings suggest. For expert lock change and installation services, speak to our team.