2026/27 STATUTORY & COST AUDIT • ICO REG ZC136598
Casement vs Flush Sash vs Vertical Sliding Sash Windows: 2026 UK Cost Matrix
How much more do flush sash and sliding sash windows cost than standard casement windows?
In 2026, standard lipped uPVC casement windows cost £380 to £520 installed, heritage flush sash casements (where the opener sits flush within the outer frame like 19th-century timber) cost £540 to £720 (+35%), and spring-balanced uPVC vertical sliding box sash windows cost £680 to £920 per aperture (+75%).
| Window Style | Installed Price Per Aperture | Conservation / Planning Suitability |
|---|---|---|
| Standard Lipped Casement uPVC | £380 – £520 | Standard Suburban Freehold Houses |
| Flush Sash Heritage uPVC (Mechanical Joints) | £540 – £720 | Article 4 Conservation Areas & Period Cottages |
| Vertical Sliding Box Sash uPVC | £680 – £920 | Victorian & Georgian Terraces |
| Thermally Broken Aluminium Casement | £620 – £880 | Contemporary Architectural Extensions |
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