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Window Security Calculator
Calculate security glazing specifications and costs for PAS 24 and BS EN 356 rated windows. Compare security levels and estimate upgrade costs for UK properties.
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Override the indicative default (0 = auto). Built-in rates are 2026 UK estimates — get supplier quotes
Labour per window fitted
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How We Calculate This
This calculator estimates security glazing specifications and costs based on security rating, window size and frame type.
The formula
Total Cost = (Glass Area × Security Glass Rate × Unit Multiplier) + (Perimeter × Frame Rate × Qty) + (Install × Qty)
- Glass cost varies by BS EN 356 / PAS 24 security rating
- Triple glazed units add ~35% to glass cost
- Frame cost per linear metre by material type
- Installation cost per window for fitting and hardware
Cost rates are indicative 2026 UK estimates for budgeting and are not governed by any standard — use the custom glass price field and obtain supplier quotes for firm pricing. The estimated U-value (double ~1.3, triple ~0.8 W/m²K) is typical of modern units; the Approved Document L replacement-window limit is 1.4 W/m²K.
UK standards
- PAS 24:2022 — Enhanced security for complete window/door assemblies
- BS EN 356 — Security glazing P1A-P8B; P1A (typically 6.8mm laminated) is the Approved Document Q minimum for glazing adjacent to accessible openings
- BS EN 12600 / BS EN ISO 12543 — Impact-safety classification (how glass breaks). This is a safety standard, not a security rating: 6.4mm laminated meets it but achieves no BS EN 356 P-rating
- Approved Document Q — Security in dwellings (England, 2015)
Working figures for this are collected in our Part Q Security Standards for Dwellings reference table.
Frequently Asked Questions
PAS 24:2022 is the UK standard for enhanced security performance of windows and doors. It tests complete window assemblies against physical attack. Most new-build properties in England require PAS 24 windows under Approved Document Q. The test involves sustained manual attack on the frame, hardware and glazing.
BS EN 356 rates security glazing from P1A to P8B. P1A-P5A test resistance to a 4.11kg steel ball dropped from increasing heights (P1A = three drops from 1.5m). P6B-P8B test resistance to a 2kg machine axe, with P6B around 30-50 strikes to cut a 400×400mm hole. P1A is the minimum required for glazing adjacent to accessible openings under Approved Document Q, and is typically achieved with 6.8mm laminated glass. For domestic security, P1A or P2A is usually sufficient; P6B and above suit commercial and high-security applications.
Yes. Laminated glass has a PVB interlayer that holds fragments together when broken, making it very difficult to penetrate. Toughened glass is stronger but shatters into small pieces allowing easy entry. For security, laminated or laminated-toughened combinations are always specified. Note that not all laminated glass is security-rated: 6.4mm laminated only meets impact-safety (BS EN 12600 / BS EN ISO 12543) and does not achieve a BS EN 356 P-rating. To reach the Approved Document Q minimum of P1A you typically need 6.8mm laminated.
Under Approved Document Q, all new-build homes in England must have windows and doors meeting PAS 24 or equivalent. This applies to conversions creating new dwellings too. Replacement windows in existing homes do not legally require PAS 24 but it is strongly recommended by police and insurers.
PAS 24 windows typically cost 15-30% more than standard. Higher BS EN 356 ratings (P2A and above) can cost 50-200% more. The main cost difference is the laminated glass and upgraded hardware. Frame costs are similar as most modern frames already meet PAS 24 with multi-point locking.
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Last updated: March 2026
Verified against UK standards · estimates only, confirm with your supplier.