The Crime Prevention Website


Windows are a main entry point for the burglar (obviously) and this section looks at the large array of windows and locks to help you understand what works and what doesn’t.  If you are considering changing your windows then please install ones that have been certificated to: PAS 24:2016 Enhanced security performance requirements for doorsets and windows in the UK. Doorsets and windows intended to offer a level of security suitable for dwellings and other buildings exposed to comparable risk (Replaces PAS 24:2012 Enhanced security performance requirements for doorsets and windows in the UK. External doorsets and windows intended to offer a level of security suitable for dwellings and other buildings exposed to comparable risk, which replaced BS 7950:1997 Specification for enhanced security performance of windows for domestic applications(See Windows of enhanced security in this chapter)

Please note:  Although manufacturer's certification will have been swapped over to the new standard you will still find references to PAS 24:2012 and BS 7950 in their brochures and on their websites.  

Common keys

Most window locks are operated by common keys.  This is not a security problem since the lock is on the inside of the window and the burglar would have to break the glass to get to the lock; something that he would be reluctant to do.  In addition, there are hundreds of different window locks and therefore a large variety of common keys making it impractical for the burglar to carry keys with him.

What is a secure window?

See Windows that should be locked for a definition  

The Disability Discrimination Act

The Disability Discrimination Act (DDA) has quite rightly made us rethink our approach to security for disabled people and, gradually, easier to use door locks and other security equipment has become available.  There are quite a few products that now meet BS 8300:2009+A1:2010 Design of buildings and their approaches to meet the needs of disabled people Code of Practice and the Building Regulation Approved Document M (ADM) (Now part of the Equality Act 2010).   If you are disabled and find it difficult to operate locks or open doors and windows it is worthwhile speaking with a member of the Master Locksmiths Association about alternative ‘easier to use’ products that have been designed with you in mind.

Some local authorities and charities help disabled and elderly people with the costs of extra security, so why not call your local council and see if they can help. 


It is perhaps not surprising that a large number of burglaries, around 15% (About 100,000 each year), involve no forced entry at all.  The thief just walks through an open door or climbs through an open window.  And you can see how this might happen.  You’re in the back garden on a hot summer’s day and unbeknown to you a thief climbs through an open window at the front of the house and steals your handbag or wallet.  It therefore follows that by simply closing windows in unoccupied rooms or by closing them all when you go out you will reduce your chances of burglary and that’s before we even talk about locks!  Of course, in the scenario given above you may feel that it is simply not practical for you to keep opening and closing windows just because you happen to be in the back garden.  This is perfectly understandable and the advice therefore is to fit the window with limiters so that the window will open only just enough to allow air to flow through the room, but keep the burglar at bay.  That said, if you do go out then make sure that you close and lock these windows.

Be aware that your insurance company may not settle a claim for your losses if there was no forced entry.  Check the small print. 

On a warm humid night many people like to sleep with a window open and providing you have considered the security risks that’s fine.  If you sleep on the first floor or above then it is unlikely that a burglar would be able to get in without disturbing you, unless of course the window is accessible as described in Security for existing windows, Windows that should be locked.  That said it is still advisable to fit the window with a lockable limiter.  If you sleep on the ground floor then you should consider fitting a security grille on the inside of the window that you commonly leave open.  It is best to use a hinged or removable grille so that you can clean the window and remember your fire safety - you may have to get out of the window in an emergency.   

Fire safety!

As a general rule most large windows on the ground or first floor of a house could be used to exit the building in an emergency and so you should ensure that the key for the window locks is as close to the window as is practical, perhaps hanging on a hook by the side of a curtain, but the key must not be visible from outside (a standard insurance requirement).  If the window is designated as an emergency escape window it is recommended that it is not key locked.  If you want to improve the security of a window that could be used for emergency escape and it happens to open onto a flat roof or emergency exit route, consider replacing the window for one that is certificated to PAS 24:2016 that has a multi-point locking function, which can be undone from the inside without the use of a key. Normally, PAS 24:2016 windows are supplied with toughened glass as standard, so make sure you ask for at least one of the panes of glass  to be a minimum of 6.4mm laminated instead. Laminated glass is more difficult for a burglar to smash and then access the keyless handle.  It is also recommended that a fine mesh grille is installed over the inner face of the opening section of the window to further prevent access to the operating handle.

If you live in a flat on the first floor then you are likely to have windows in each room which are large enough to escape through without the use of a key.  Unless this type of window opens onto a flat roof it is highly unlikely to be a point of entry for a burglar, so you don’t need to fit it with locks and shouldn’t anyway.  That said you may want to fit safety devices to prevent a child opening the window and falling out.  These devices do not use keys, because it is important that you are able to use the window in an emergency.  Even child safety catches can be hazardous in fires, which is why you must have working smoke detectors and a fire plan in place. 

Insurance requirements 

An ‘escape’ window, not fitted with key-operated locks, may put you at loggerheads with your insurance company.  As this window was probably a Building Regulation requirement it would be unwise to fit a key-operated lock.  However it can be grilled as discussed above and replaced with one to PAS 24:2016 with laminated glass.  I strongly recommend that you speak and write to your insurers to reach an agreement about this issue.

Do carefully read you insurer’s requirements for window locks as they usually require them on windows near to soil pipes, rainwater pipes (even plastic ones), trees and shrubs. 

A bit of history

In the 17th century the first type of opening window used in Britain was the casement with side hinges.  Poor people, who would not have been able to afford glass, would instead stretch linen soaked in linseed oil across the wooden frame in order to let some light into the home, but keep the drafts out.  At night these would have been further protected by wooden shutters. By the second half of the 17th century sliding sash windows were developed and even people on modest incomes started to use glass - small panes though!


I am very grateful to Thames Valley Police’s Crime Prevention Design Adviser, Dave Stubbs MA PG Cert. Ad. Cert. CP & ED, for reading through these sections and providing some interesting information that I forgot to include.