The facts about home insurance window locks

---

A safe and secure home not only gives you peace of mind, but it also keeps your insurer happy! But what exactly does an insurance company expect when it comes to windows, and could yours be at risk of invalidating your home insurance policy?  Quotezone can find your perfect home insurance provider with its independent comparison tool, and now let’s see what these insurers will expect when it comes to your windows.

---

What are window lock insurance requirements?

UK home insurers typically require one or more of the following on accessible windows:

• Key-operated window locks on all opening windows that are accessible from outside
• BS 3621 certified locks for the highest level of security (often required for jewellery or high-value contents)
• Sash window stops on older sash windows
• Multi-point locking systems on UPVC and composite windows

If your insurer specifies window lock requirements and you don’t meet them, a claim involving break-in through a window can be rejected. Always check your policy wording when buying cover – different insurers have different rules, and some give discounts for approved locks.

What are accessible windows?

Accessible windows are any windows a burglar could reach without equipment. Most insurers define this as windows that are:

• At ground floor level – any ground floor window, front or back
• Reachable from a flat roof – typically porches, extensions, and garage roofs
• Near a climbable feature – drainpipes, sturdy trellises, garden sheds, or wheelie bins stored underneath
• On a balcony or fire escape – including upper floors

Upper floor windows that can only be reached with a ladder are not usually considered accessible. If you’re unsure which of your windows count, ask your insurer or check the policy wording before you buy – getting this wrong could affect a future claim.

Does my window lock have to be key-operated?

For most UK home insurance policies, yes – key-operated window locks are the standard expectation on accessible windows. This is because they can’t be opened by someone reaching through a broken pane or using a screwdriver on the handle.

A key-operated lock requires a physical key to unlock, making forced entry significantly harder. The burglar would either need to find the key, break the lock, or smash enough glass to climb through – all of which take time and make noise.

Some older properties with period windows may not be able to accommodate key-operated locks without damaging original features. In these cases, insurers often accept:

• Secondary key-operated locks fitted alongside existing catches
• Sash window stops with keys
• Security film or laminated glass combined with existing catches

Always check with your insurer before assuming non-key alternatives are acceptable.

Do home insurance window lock rules apply to all types of windows?

You may have noticed that modern UPVC, aluminium or timber framed windows usually come pre-fitted with locks, but older styles and period examples do not.  Just because your older windows don’t currently feature locks, this does not omit you from window lock insurance requirements.

Older-style wooden windows such as sash and wooden casements can be easily fitted with locks or security devices.  For example, an insurer may ask that sash windows have a heritage fitch, quadrant sash or Brighton sash fastener installed.  Casement windows may require casement fasteners, stays or locks. Many traditional window styles can also be fitted with a device known as a stopper.

You can double-check that the devices you’re using will be accepted by your insurer by making sure they comply with the BS3621 lock standard.

When do I need to keep my windows locked?

Most UK home insurance policies require you to keep windows locked when:

• The property is unoccupied – even for a short trip to the shops
• Overnight – especially on ground floor windows
• During extended absences – holidays, work trips, or properties left unoccupied for more than 30 days

Some policies are stricter than others. A few insurers require windows to be locked at all times unless you’re in the room – others only require locking when the property is empty. Read the policy wording carefully, especially the “reasonable care” clause.

If your home is burgled through an unlocked window, your insurer may reduce or reject your claim. Keeping windows locked when not in use is a simple habit that protects both your home and your cover.

Are there benefits to having window locks, other than security?

Most insurers insist on you having window locks on accessible windows in order to keep a home insurance policy valid – so window locks mean you benefit from the security of home insurance protection.

One of the other big benefits is that you’ll make savings on your insurance premium if you can demonstrate that your window locks or devices comply with the British Standards Institute for thief-resistant locks (BS3621).

If you’re ready to protect your home with a new home insurance policy, compare quotes now.

What window locks do insurers approve?

UK insurers typically require window locks that meet British Standard BS 3621 or a key-operated locking mechanism. Without approved locks, your home insurance may not pay out if someone breaks in through a window.

Common insurer-approved locks include:

• Key-operated window locks – a lock that requires a key to open and close. Most modern UPVC windows have these built in.
• Sash stops – for sash windows, small metal stops that prevent the window from opening beyond a set point.
• Multi-point locking systems – found on newer UPVC and aluminium windows, these lock the frame at several points.
• Casement locks – keyed locks fitted to casement window handles.

If you live in an older property with original timber windows, your insurer may accept secondary locks fitted alongside the existing catch, as long as they’re key-operated. Always check your policy wording – some insurers specify the exact type of lock they expect, particularly on ground floor and accessible windows.

What happens if you leave a window open and get burgled?

If a burglar enters through a window you left open or unlocked, your insurer may refuse to pay out. Most UK home insurance policies require you to take reasonable care to secure your home, and an open window usually counts as a failure to do so.

The rules typically apply when:

• The property is unoccupied (even for a short trip to the shops)
• You’re asleep overnight with a ground floor window open
• The window is on an accessible route (ground floor, or near a flat roof, drainpipe, or garden shed)

If you have the window open while you’re at home and awake, and a thief still gets in, your policy will usually still cover the claim. But the specifics depend on the wording, so read your policy carefully – some insurers have strict “windows must be locked when the property is unoccupied” clauses.

Does home insurance cover the window itself?

Yes, most home insurance policies cover damage to the windows themselves. Buildings insurance covers the frames, glazing, and fittings as part of the property structure, so if a window is smashed – by a storm, falling tree branch, or attempted break-in – the repair or replacement is usually covered.

Accidental damage (say, a child breaking a window with a football) may not be covered by default. Many insurers offer accidental damage as an optional add-on for an extra £20 to £50 a year.

Contents insurance covers things inside the home, not the windows themselves. But if a broken window leads to rain or storm damage to your belongings, contents cover would usually pay for replacing those items.

You might also need

When thinking about home security and insurance, you may also want to consider:

• Buildings insurance – covers the structure of your home, including windows, doors, and permanent fixtures.
• Home emergency cover – covers the cost of emergency call-outs if you’re locked out or need urgent repairs.

Quotezone can help you find home insurance that matches your security setup. Compare home insurance quotes from over 40 UK providers.

---

This article is intended as generic information only and is not intended to apply to anybody’s specific circumstances, demands or needs. The views expressed are not intended to provide any financial service or to give any recommendation or advice. Products and services are only mentioned for illustrative rather than promotional purposes.

---