Buyer’s Guide to Door Locks & Latches

Locks and latches (1)

From deadbolts to rim locks, mortice latches to sash locks, this door locks & latches buyer’s guide will explain the different latching and locking options out there for ensuring privacy and security in your home. We will also discuss which door lock to buy for houses of multiple occupancy (HMOs) and commercial properties.

What are the different types of door locks?

When looking for new or replacement locks, it can be easy to look at your door and ask “What door lock or mechanism do I have?” So here, we’ll first go through the different door locks and how to identify them.

Sash Locks 3-Lever and 5-Lever (standard lever key)

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Sash locks are locks that contain a key-operated bolt and a latchbolt. These locks are a versatile and recognisable choice for many doors — from storage doors in commercial buildings,  to entry doors in residential buildings. A sash lock can be locked from either side of the door by key or thumb turn, and the latch keeps the entry closed despite being unlocked. Sashlocks are

A 5-lever lock is one that uses 5 levers for its locking mechanism. It sounds obvious, but what this means is that they are more secure than 3 lever locks because there is a greater chance of key duplication, and or lock picking. These locks will have the British Standard Kitemark engraved on the faceplate of the lock, and will often have the standard number engraved on the faceplate, too. This marking is recognised by UK insurers and in most cases is a necessity. A 3-Lever sash lock is the same as above but just less secure, uses smaller keys, and is more suited to locking interior doors such as a study or bedroom.

Wherever a sash lock is to be fitted, a set of handles or knobs would be required.

Mortice Deadlocks — 3-Lever and 5-Lever (standard lever key)

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Mortice deadlocks are locking mechanisms that only require a key to operate. There are no handles or doorknobs required on these key-operated deadlocks. These are simple and easy ways of keeping a doorway securely closed. Unlike sash locks, deadlocks do not include a latch; so they must be locked to ensure the door is locked.. Deadlocks are often used as additional security, such as when paired with a night latch (commonly referred to as a Yale lock) on front doors, outbuildings, or on lockable doors in shared rental properties (or Houses of Multiple Occupancy).

An easy way to identify a mortice deadlock is that they are not found on uPVC and composite doors. They are mostly found on wooden doors, open with a key, and the lock morticed into the edge of the door, not the surface.

Euro Profile Cylinders & Locks

Euro lock (1)

Euro profile cylinder locks are generally seen on external doors because of their multitude of uses.. They must be installed along with a euro profile mortice lock case and can be used in many different situations.. Euro Profile cylinders come in a multitude of various sizes and finishes, and also have the option of key both sides, key / thumburn, or a single sided ‘half’ cylinder version.

Euro profile cylinders can be specified for use internally or externally, and when used to lock doors internally (domestic or commercial), the thumbturn option offers escape from the room in the event of a fire. A full range of euro profile mortice sashlock and deadlock cases are available to suit these cylinders.

Bathroom Mortice Lock Types

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Bathroom Mortice Sash Locks

Bathroom mortice locks are used for internal doors which require a locking/privacy function. A mortice bathroom lock would generally be used with a set of bathroom furniture, or fitted with a set of handles with a matching separate thumbturn & release.

Bathroom deadbolts

bathroom deadbolts can be used when a bathroom turn is required, either on its own or fitted alongside a tubular mortice latch. Often specified when using a door handle set on roses, along with a matching bathroom turn, allowing for the spacing between the two to be decided on site. A simple 90deg turn will throw the bolt into the keep on the frame.

Deadlock (1)

Rim Night Latches

Rim night latch (1)

Rim night latches are also commonly known as ‘Yale’ locks and are most often found on external entry doors. These locks use a spring-loaded latch that keeps a doorway secure and firmly closed. These latches open on the inside with a thumb turn, and via key on the outside, and many can be double locked for extra security. Most rim nightlatches feature hold back snib on the case which enables the latchbolt to be held in the open position. A rim night latch is secured to the surface of the door, rather than inside the door, as well as other rim locks. A night latch is useful for its automatic locking upon closing the door, offering peace of mind.

In most domestic front door situations,, a night latch will be used in combination with a 5-Lever deadlock to improve overall security and these two elements on a door will gain the BS3621 status for insurance purposes. 

Digital Combination Door Locks

Combination lock (1)

These combination door locks use a keypad with a programmable code to keep internal and external entries secured. Because these locks make it easy to keep personal offices or storerooms locked, or designated service areas in rental properties locked, these are common in commercial buildings and in buildings with many occupants such as a block of flats.

A combination lock requires the memorisation of a code of keypresses externally but uses a thumb turn on the interior side of the door allowing for ease of egress.

Rim Locks

Attached to the surface of the door, rather than sunk into the door itself, a rim lock is available as both a sash lock and a deadlock depending on needs. These locks are commonly found on internal doors in many older period properties,  and also have a general use such as on garden sheds or gates. Rim locks also perform exceptionally well in period properties as these were more common throughout history due to their simpler installation on the outside of the door. Special ‘rim knob’ furniture must be used wherever these locks are fitted. Sometimes an original lock can be kept, and the knobs upgraded as in the image below:

Rim lock (1)

How do door locks work?

Generally, a lock activates levers inside the mechanism which extrudes a bolt into the frame of a doorway or secured catch on the surface of the frame. Locks are either sprung or manually turned, and when engaged a lock prevents the door from opening.

Regardless of how a lock is constructed, all locks use a bolt or latch mechanism to keep a door secure. Some door locks, particularly Euro-style cylinder locks, engage multiple-point locking systems which include extra engaging bolts at the top and bottom of the door. These multi-point locking systems are common in composite or uPVC doors, but not wooden doors.

Which door lock is best?

It’s hard to judge which door lock would be best for a property unless everything at the property is taken into account. However, generally, more security should be used on external doors or doors that lead to secure areas in commercial buildings.

When door material is a concern, in period properties, for example, there may be certain lock systems that you will not be able to use. A multi-point locking system is usually only found on more modern composite or uPVC doors, for example.

What should also be considered for which door lock is best for your situation is who will be using the lock and what type of entry is required. Let’s go through some of the planning considerations that new locks and latches will require.

How to plan for new locks & latches

Door location

Where the door is located is a key aspect for which lock or latch to choose. Different areas of the home, or a commercial building, will require different locks or latches. An internal door to the living room will likely not need a lock but would need a latch, whereas your front door will always require a lock.

The type of lock you choose for your front door, or other external doors, will depend on what kind of access you and others require. Let’s go through some of the other aspects here.

Lock Strength

Depending on the type of property and the door location, a strength and security standard may be required; for example, if your insurance provider wants a specific lock type. A 5 lever mortice lock that conforms to the British Standard is typically approved by most insurers for use in homes — as long as they are marked BS3621.

Fire safety

Fire safety should always be considered, but in commercial or some residential settings fire safety is a requirement. Houses of multiple occupants (HMOs), rental property entrances, or rooms over two levels for example all require fire-rated doors, frames, strips, and locks with matching FD ratings.

Door material

Depending, once again, on where the door is located or what type of building the door is installed in, the door material can be an important factor in planning for a new lock or latch. Certain locks may only be compatible with particular materials like composite designs or uPVC.

Euro profile cylinder locks are a great option for lightweight doors, but solid timber doors are strong enough for 5 lever mortice fixtures and deadbolts.


It is essential to consider accessibility when considering which lock or latch to purchase. A deadlock and night latch should be installed at the right heights to be comfortable to use. In some cases, wheelchair height accessible locks is a requirement, or is a good idea, and can influence your choice of lock.

Keyless locking, such as turn-operated locks or bathroom privacy latches, can often be secured with minimal effort. Bathroom turns for the less-able are available, which have a longer more tactile turn making it easier to operate.

Replacement fittings

If you are replacing a lock, rather than buying a new lock entirely, you should ensure that you measure the current locking components so that a direct match can be found. This makes the replacement process simpler. The most important elements to measure are the size and depth of the existing lock case, for mortice lock cases, as this will allow for a simple swap of the new case; screw holes and the cavity should be in the same place with exact matches.

Colour and Style

If you are securing a period property, or you are putting a lock on a modern front door, you should be considering the colour and style of the fittings you are purchasing. A period property might suit a From the Anvil style traditionally manufactured rim lock, rather than a polished chrome night latch, for example.

Some locks are visible externally, such as night latches or rim locks, and it’s vital to consider the style of the property to retain a consistent look, tone, or feeling.

Additional Security

Particularly for external doors, additional security features such as secondary bolts or chains can deter or prevent potential intruders. Extra bolts or chains can improve the physical strength of a doorway, whilst CCTV systems, security lights, and an alarm can also prove effective.

Explore all of our door locks and latches

We host a wide range of door locks and latches on Handles4Homes, and we’re happy to speak with you about your needs if you cannot find something that suits your exact requirements. 

Our full range of door locks and door latches has many options for you to choose from and look through.

Contact us today if you want to speak to an expert about your needs.

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