Window security ratings for UK homes

The average UK home is broken into through a door or window in the overwhelming majority of residential burglaries, according to Office for National Statistics crime data. Yet most homeowners who invest in new glazing focus almost entirely on thermal performance and appearance, giving little thought to whether the product they are fitting will actually withstand a determined attempt at entry. Window security ratings exist precisely to close this gap — they give you an objective, independently verified measure of how well a window performs under real-world attack conditions. Understanding what these ratings mean, which ones carry genuine weight, and which are little more than marketing language could make a meaningful difference both to your home’s security and to your insurance position.

Why Window Security Ratings Matter More Than Most Homeowners Realise

There is a widespread and understandable assumption that any double-glazed window is a secure window. In practice, the thermal performance of a window and its resistance to forced entry are almost entirely separate considerations. A window can achieve an excellent energy efficiency rating and still fail a basic physical attack test within seconds. The frame material, the quality of the locking hardware, the hinge specification, and the way the glazing unit is retained within the frame all contribute to security performance — none of which are captured by a Window Energy Rating (WER) or U-value figure.

The stakes for getting this wrong are higher than many homeowners appreciate. Insurers are increasingly specific about the window standards they expect, and a policy document that references compliance with a recognised security specification is not merely a suggestion. If you submit a burglary claim and it emerges that your windows did not meet the standard your insurer assumed, the claim can be challenged or refused. In 2026, with a broader and more competitive window market than ever before, the temptation for less scrupulous suppliers to use reassuring-sounding language — “high security,” “enhanced protection,” “police approved” — without any verifiable standard behind it is considerable. Knowing what to look for protects you from paying a premium for language rather than performance.

According to the Energy Saving Trust and broader housing research, ground-floor windows and easily accessible upper-floor openings remain among the most commonly exploited entry points for opportunist burglars. These are the very windows most homeowners replace most frequently, yet security compliance is rarely part of the specification conversation in the way that draught-proofing or glazing thickness might be.

Practical tip — Before your next window quote, write down the words “PAS 24 certificate” and ask every installer you speak to whether they can provide one for the specific product they are proposing. A confident yes is a good sign. Hesitation is a warning sign worth heeding.

The Basics of Window Security Testing in the UK

What separates a meaningful security rating from a marketing claim is independent, standardised testing. In the UK, window security ratings are determined by physical attack tests carried out by accredited laboratories operating under UKAS (United Kingdom Accreditation Service) oversight. These are not self-certified assessments — manufacturers cannot award themselves a security rating by filling in a form or paying a fee to a trade body. The testing process involves trained technicians subjecting windows to a series of progressively demanding attacks, and the product either passes or it does not.

The tests simulate the kinds of tools and techniques an opportunist burglar would realistically use. Crowbars, screwdrivers, bolt cutters, and hammers are all part of the standard attack toolkit used in laboratory conditions. The attacks are applied to every vulnerable element of the window system — the frame, the glazing, the hinges, and the locking hardware — and the test must be completed without the window being breached within a defined time period. That time element matters because most opportunist break-ins are abandoned within a few minutes if entry is not gained quickly.

The British Standards Institution (BSI) plays a central role in developing and maintaining the standards that underpin these tests, and UKAS-accredited third-party certification bodies provide the independent verification that gives the resulting ratings their credibility. This structure means that when a supplier tells you a product is certified to a recognised standard, there is a verifiable paper trail behind that claim — a test certificate from a named laboratory, referencing a specific standard, for a specific product configuration. That certificate is something you should feel entirely comfortable asking to see.

guide to choosing double glazing installers and checking credentials

Practical tip — Ask your supplier to share not just the name of the standard but the actual test certificate, including the laboratory name and the specific product or system reference. A certificate that matches the product being quoted is very different from a generic brochure claim.

What PAS 24 Actually Means for Your Windows

PAS 24 — which stands for Publicly Available Specification 24 — is the cornerstone of domestic window security in the UK. It is the enhanced security standard for doors and windows that forms the basis of Approved Document Q, the section of England’s Building Regulations that governs physical security in new homes. If you have recently moved into a new-build property or are looking at windows fitted in a property built in the last decade, PAS 24 compliance should already be a baseline expectation.

To achieve PAS 24 certification, a window must pass a comprehensive battery of tests. These cover manipulation of the locking mechanisms, physical attack on the frame and glazing, and environmental performance across a range of conditions. Crucially, it is the complete window system that is tested — frame, glazing unit, locks, hinges, and any other hardware — assembled and fitted exactly as it would be in a real installation. A lock that passes its own individual test is not sufficient; it must perform as part of the whole system.

For new-build homes in England, PAS 24 compliance is not optional. Approved Document Q requires that all accessible ground-floor windows and any other windows that could reasonably be reached without a ladder in a new dwelling must meet this standard. This requirement applies as of 2026 and has done so for a number of years, meaning there is no legitimate reason for a new-build window specification to lack PAS 24 certification.

For homeowners replacing windows in an existing property, the position is slightly different. While PAS 24 is not always a strict legal requirement for replacement windows in existing homes (as opposed to new-builds), it is strongly recommended, widely adopted by quality installers, and increasingly expected by insurers. If you are replacing windows through a competent person scheme such as FENSA or Certass, your installer is responsible for ensuring the installation complies with relevant Building Regulations — and that includes security performance where Approved Document Q applies.

Building Regulations and replacement windows — what homeowners need to know

Practical tip — When you receive a quote for replacement windows, specifically ask whether the product carries PAS 24 certification and request the certificate number so you can verify it independently if you choose to.

Secured by Design and What the Police-Backed Scheme Involves

Secured by Design (SbD) is a police-backed accreditation programme operated by the National Police Chiefs’ Council (NPCC). It is not a government regulation and it is not a legal requirement, but it represents a higher bar than the minimum standards set by Building Regulations and is widely regarded by security professionals, insurers, and planning authorities as best practice for domestic window security.

To display the Secured by Design logo on a window product, a manufacturer must go through a formal licencing process with the NPCC. This involves demonstrating that every security-critical component in the window system — the locks, the hinges, the glazing — meets relevant individual standards, and that the complete, assembled product meets PAS 24 or its equivalent. Manufacturers are also subject to regular audits to maintain their licenced status, which means the accreditation is not a one-time box-ticking exercise.

The full list of SbD-licenced products is publicly searchable on the Secured by Design website at securedbydesign.com. This is an important resource for homeowners because it allows you to cross-reference your installer’s claims before you sign any contract. If a supplier tells you their product is Secured by Design approved but the product does not appear in the online database, that discrepancy deserves a clear explanation.

Secured by Design windows are recommended by police forces across the UK, by the government’s Design Out Crime programme, and by a growing number of home insurers. The scheme has decades of research behind it showing that SbD-rated products are statistically associated with lower rates of successful burglary in the areas where they are installed. This is not abstract theory — it is the reason new-build developments seeking planning approval are often encouraged or required by local planning conditions to include SbD specification windows as part of a broader crime prevention strategy.

Practical tip — Use the Secured by Design product search at securedbydesign.com before finalising any window purchase. It takes a few minutes and gives you independent confirmation that the product matches the installer’s claims.

Other Ratings and Marks You May See on Window Products

Beyond PAS 24 and Secured by Design, the window market includes a range of other standards, certification marks, and classification systems. Understanding what these mean — and, importantly, what they do not mean — helps you interpret a product specification accurately rather than being reassured by unfamiliar-sounding terminology.

BS 7950 is an older British Standard for enhanced security windows that predates PAS 24. It is now largely superseded and is no longer the reference standard for new installations, though some older properties may have windows that were certified to it. If a supplier references BS 7950 as evidence of current security compliance for a new product, it is worth asking whether the product has been tested to PAS 24 as well.

RC ratings (Resistance Class) are a European classification system defined by EN 1627. The scale runs from RC1, which offers very basic resistance, through to RC6, which is used in high-security institutional and government settings. For domestic UK purposes, RC2 is broadly comparable to PAS 24 in terms of the level of attack resistance it represents. RC3 and above are typically specified for commercial premises, cash-handling environments, or high-value residential properties with a specific elevated risk profile.

The BSI Kitemark and Q-Mark are product certification marks from independent certification bodies. When you see a Kitemark on a window, it confirms that an independent body has tested the product against the standard claimed and verified the manufacturer’s quality control processes. The Kitemark is not a security standard in itself, but it adds a layer of verified credibility to whatever standard the window is certified against.

Proprietary marketing terms such as “Diamond 9 security glass,” “ultra-secure profile,” or similar brand-specific language are not standardised ratings. They may describe genuinely good products, or they may describe entirely ordinary ones dressed in impressive-sounding vocabulary. The test is always to ask which recognised standard underlies the claim. For glass attack resistance specifically, EN 356 is the relevant European standard — a product described as “security glass” should ideally reference its EN 356 classification (such as P4A or P5A) rather than a brand name alone.

understanding window energy ratings and glazing specifications

Practical tip — When faced with an unfamiliar term on a window specification, ask the supplier to tell you which BSI, PAS, or EN standard it corresponds to. If there is no underlying standard reference, treat the term as marketing language rather than technical evidence.

Security Standards Compared at a Glance

Always verify with your supplier which standard applies to the specific product as a complete system, not just the frame profile or the glazing unit in isolation. A highly rated frame paired with a basic lock will not achieve a meaningful overall security rating.

Which Security Level Is Right for Your Home

Not every home carries the same level of risk, and the right window security specification should reflect your property’s individual circumstances as well as a sensible baseline. That said, there is a floor below which it is genuinely unwise to go, regardless of where you live.

For most standard suburban homes without specific elevated risk factors, PAS 24 certified windows on all ground-floor openings and any upper-floor windows accessible without a ladder represent a solid, regulation-compliant baseline. This level of protection is designed to deter and delay the opportunist burglar — the most common type — rather than resist a determined, prolonged attack. For the vast majority of UK residential properties, this is an appropriate and proportionate specification.

For homes in higher burglary-risk areas, the calculus shifts. You can check your area’s crime profile using the police.uk crime mapping tool, which provides postcode-level data on reported residential burglaries. If your area shows elevated rates, consider specifying Secured by Design-licenced windows as a minimum, and look at adding laminated glass to EN 356 P4A classification or above. Laminated glass holds together rather than shattering when struck, significantly slowing or preventing entry through the glazing itself rather than via the frame and lock.

Ground-floor flats, corner properties, and homes adjacent to alleyways, footpaths, or poorly lit communal areas are consistently identified in NPCC guidance as higher-risk entry points. These property types benefit most meaningfully from SbD-rated installations, and in some cases a conversation with your local police architectural liaison officer — a free service available in most UK police forces — can provide tailored advice for your specific property.

Listed buildings and properties in conservation areas present a particular challenge because planning restrictions may limit the visual changes you can make to the external appearance of windows. However, this does not mean security compliance is unachievable. A number of specialist manufacturers offer slim-profile timber and aluminium windows that meet PAS 24 certification while maintaining a heritage-appropriate appearance. Always confirm your specification with your local planning authority before proceeding, and ask potential suppliers to provide examples of planning-approved heritage window installations that include PAS 24 certification documentation.

windows in listed buildings and conservation areas — a homeowner’s guide

Practical tip — Check your postcode on police.uk before specifying windows for a replacement project. If your area shows a meaningful number of reported residential burglaries, treat SbD accreditation as your minimum rather than PAS 24 alone.

What to Look for When Buying or Replacing Windows in 2026

Armed with an understanding of the standards, the practical next step is knowing how to apply that knowledge when speaking to installers and making purchasing decisions.

The single most important action you can take is to ask for the actual PAS 24 test certificate for the specific product being quoted. This is a formal document, not a brochure or a badge on a website. It should identify the certifying laboratory by name, reference the specific window system by its product designation, and confirm the standard it was tested against. A reputable, experienced installer will have this document readily available and will not hesitate to share it. If an installer cannot produce it or deflects by offering general reassurances instead, that is a significant red flag.

Check whether your installer is registered with a Competent Person Scheme. FENSA (Fenestration Self-Assessment Scheme) and Certass are the two principal schemes for replacement window installers in England and Wales. Registered installers are authorised to self-certify their installation work against Building Regulations, including the security performance requirements of Approved Document Q. Registration with one of these schemes does not guarantee quality, but it does mean the installer is subject to oversight and that you will receive a certificate of compliance on completion of the work — which you will need when you sell the property.

Look for specific hardware features within the window system. Multipoint locking mechanisms that engage at multiple points along the window frame, rather than at a single central point, dramatically increase resistance to levering attacks. Reinforced hinges with integrated anti-jemmy features are equally important, particularly for side-hung casement windows which are inherently more vulnerable at the hinge side. Anti-snap, anti-drill cylinder locks — essential for composite and timber entrance doors — are less relevant for windows but are worth noting if your property also has patio or sliding doors with cylinder-based locking systems.

If you are looking at windows for a property with particularly generous or low-set glazing panels, the specification of the glass itself deserves attention. Standard float glass offers very little resistance to attack — a direct blow will shatter it quickly. Laminated glass, in which a plastic interlayer holds the pane together when broken, is a worthwhile upgrade for ground-floor windows in higher-risk settings and is referenced in EN 356 classifications.

Practical tip — Verify your installer’s FENSA or Certass registration on the relevant website before signing a contract. Registration can be checked free of charge using the installer’s company name or postcode.

How Window Security Ratings Can Affect Your Home Insurance in 2026

The relationship between window security and home insurance is one that many homeowners do not fully explore until they find themselves in the uncomfortable position of making a claim. By that point, any gaps in their window specification may have already become a problem.

Some insurers in 2026 explicitly reference PAS 24 or Secured by Design compliance in their policy documents, either as a condition of certain levels of cover or as a factor in premium calculations. Others operate on the assumption that windows in UK homes meet a minimum standard without making this explicit in consumer-facing documentation — but the small print of the policy terms may contain wording that has the same practical effect. The Association of British Insurers (ABI) consistently advises homeowners to confirm their window specification with their insurer when undertaking any replacement glazing project, precisely because of the potential for misunderstanding in this area.

If you are applying for a new home insurance policy, disclose your window security specification accurately. If your windows are PAS 24 or SbD certified, this is worth stating clearly — it may improve the premium offered or avoid the application of exclusions related to inadequate security. If your windows are older and do not meet current standards, do not assume your insurer shares that assumption. Check directly.

The consequences of a mismatch between what your insurer assumes and what your windows actually are can be severe. A successful burglary claim contested on the grounds that your windows did not meet the standard referenced in your policy could result in a significantly reduced payout or a refusal to pay at all. This is not a theoretical risk — it is a documented reason for disputed claims in residential burglary cases in the UK.

If you are planning a window replacement project in 2026, it is worth notifying your insurer in advance, confirming the specification you intend to install, and asking for written confirmation that the new windows will satisfy their requirements. This takes a single phone call or email and removes any ambiguity from your position going forward.

Practical tip — Contact your home insurer before replacing windows and ask specifically whether the product specification you are considering satisfies their security requirements. Get the confirmation in writing, even if it is just an email.

Financial Support for Window Upgrades in 2026

Window replacement is a meaningful financial investment, and understanding what support might be available is a sensible part of the planning process. In 2026, the primary public funding routes for home improvements focus on energy efficiency rather than security specifically, but there is often an opportunity to align both objectives within the same project.

The ECO4 scheme (Energy Company Obligation 4), administered through energy suppliers and overseen by Ofgem, provides funding for energy efficiency improvements in lower-income and vulnerable households. Window replacement is not the primary focus of ECO4, but if you are eligible and a broader ECO4 package is being funded for your home, it is entirely reasonable to specify that any replacement windows included in the works are PAS 24 certified. This typically adds little or no cost to the project and means you receive security compliance as part of an energy efficiency installation. Eligibility for ECO4 is means-tested — check the current criteria via the government’s Simple Energy Advice service or contact your energy supplier directly.

The Great British Insulation Scheme, also operating in 2026, similarly focuses on thermal performance and primarily targets loft and wall insulation rather than glazing. However, where windows are being replaced as part of a broader energy improvement programme, the same principle of specifying security-compliant products at the point of installation applies.

For homeowners not eligible for grant funding, it is worth noting that the cost premium for PAS 24 certified windows over non-certified alternatives is generally modest when purchasing from reputable suppliers. In 2026, a typical uPVC double-glazed casement window to PAS 24 standard from a quality installer costs in the region of £400 to £700 per window including fitting for a standard size, depending on location and supplier. The premium for SbD-licenced over standard PAS 24 is typically small — the bigger variables in window pricing tend to be material choice (uPVC versus aluminium versus timber), glazing specification, and installer location rather than the security standard itself.

ECO4 and home improvement grants — what UK homeowners can claim in 2026

how to choose a window installer — questions to ask before you sign

Practical tip — If you are having any windows replaced under a funded energy efficiency scheme, add the words “PAS 24 certified” to your specification in writing before work begins. It costs you nothing and means any new windows installed will meet the security standard your insurer expects.

Putting It All Together

Window security ratings in the UK are not complex once you understand the structure behind them. PAS 24 is the baseline — independently tested, referenced in Building Regulations, and non-negotiable for new-build homes and increasingly expected for replacement windows. Secured by Design is the police-backed step beyond that, verified through regular auditing and publicly searchable, and it represents best practice for homeowners who want to align their windows with the standard that UK police and insurers consistently recommend.

Beyond these two core references, understanding RC ratings, EN 356 glass classifications, and the distinction between a BSI Kitemark and a manufacturer’s own branding gives you the literacy to evaluate any supplier’s claims with confidence rather than taking reassuring language at face value.

The practical steps are straightforward. Ask for test certificates, verify installer registration with FENSA or Certass, check the Secured by Design product database, and have a clear conversation with your insurer before and after any replacement project. Done properly, replacing your windows in 2026 is an opportunity to significantly raise both the thermal performance and the security performance of your home simultaneously — and to ensure that improvement is documented in a way that protects your insurance position for years to come.