Timber Window and Door Certificates
Performance Certificates & Test Reports for Timber Windows and Doors
Our timber window and door certificates confirm that every timber sash window, casement window, and door we supply has been independently tested to meet the highest UK standards for energy efficiency, weather performance, and security.
From verified U-Value certification to PAS 24 testing, each report is issued by a UKAS-accredited testing body, providing homeowners, architects, and developers with complete confidence in compliance and performance.
Our Certificates & Test Reports
U-Value Certificates
- U-Value Certificate – Sash Window (Cords & Weights)
- U-Value Certificate – Spiral Balance Sash Window
- U-Value Certificate – Timber Casement Window 79mm x 70mm
- U-Value Certificate – Timber Single Door with Solid Panel 79mm x 70mm
- U-Value Certificate – Timber Single Door with Glass Panel 79mm x 70mm
- U-Value Certificate – Timber Double Door with Solid Midrail 79mm x 70mm
- U-Value Certificate – Timber Double Door with Glass Panel 79mm x 70mm
PAS24 Certificates
Why Performance Testing Matters
Independent testing ensures every window and door performs as expected – from insulation and weather resistance to security and durability.
A certified U-Value gives a true measure of thermal efficiency, reducing heat loss and helping meet Part L of the Building Regulations. Similarly, PAS 24 testing provides assurance that products can withstand attempted forced entry, supporting compliance with Part Q and Secure by Design requirements.
Why PAS 24 Certification is Important
PAS 24 certification demonstrates that a window or door has undergone comprehensive strength, impact, and mechanical tests.
It ensures that timber joinery can meet modern security standards without compromising traditional detailing – particularly important for conservation and heritage projects.
Products tested to PAS 24 are suitable for new-build dwellings, conversions, and renovation projects seeking enhanced protection and peace of mind.
Our Certificates & Test Reports
Each product range has been independently tested and certified to verify energy efficiency and compliance with current Building Regulations.
All tests were carried out by ERC Testing Ltd, a UKAS-accredited laboratory (Accreditation No. 23361) and registered company with the Ministry of Housing, Communities and Local Government (MHCLG No. 8544).
Below is the full list of test certificates available on request:
| Product Type | Report Number | Thermal Transmittance (U-Value) | Centre Pane U-Value (Ug) | Notes |
|---|---|---|---|---|
| Sliding Sash Window (Cords & Weights) | 901154 | 1.2 W/m²K | 1.042 W/m²K | Tested using 4/16/4 Planitherm One double glazing |
| Sliding Sash Window (Spiral Balance) | 901153 | 1.2 W/m²K | 1.042 W/m²K | Verified thermal performance with concealed spiral system |
| Casement Inline Window | 901032 REV 1 | 1.2 W/m²K | 1.045 W/m²K | Tested softwood frame with 4/16/4 Planitherm One glazing |
| Single Door (Full Glass) | 901151 | 1.1 W/m²K | 1.042 W/m²K | Full-height glazed timber door |
| Single Door (Glass & Panel) | 901152 | 1.3 W/m²K | 1.042 W/m²K | Door incorporating insulated timber panel |
| Single Door (Solid Panel) | 901150 | 1.4 W/m²K | 1.458 W/m²K (panel) | Fully solid timber panel door |
| Double Door (Full Glass) | 901149 | 1.1 W/m²K | 1.042 W/m²K | Pair of fully glazed double doors |
| Double Door (With Midrail) | 901148 | 1.3 W/m²K | 1.042 W/m²K | Glazed double doors with midrail and insulated panel |
All reports were conducted using WINISO (Version 2.8.1) thermal simulation software and verified for compliance with Approved Document L.
Who Issues Our Certificates
All testing is carried out by ERC Testing Ltd, an independent, UKAS-accredited body (Accreditation No. 23361) and MHCLG-registered testing laboratory (No. 8544).
ERC Testing operates from their facility in Leigh, Lancashire, and specialises in the verification of thermal performance for timber, aluminium, and composite windows and doors.
Each test confirms the whole-unit U-Value rather than just the glass centre pane, ensuring realistic performance data that reflects complete product construction — including frame, sash, seals, and glazing.
These independently issued certificates demonstrate our commitment to verified performance, transparency, and Building Regulation compliance across our entire timber range.
Benefits of Certified Timber Windows & Doors
Building Regulation Compliance – Verified performance data for Parts L, Q, and M.
Energy Efficiency – Reduced heat loss and lower long-term energy costs.
Security Assurance – Independently tested to withstand forced entry.
Architectural Confidence – Clear documentation for specification, tender, and warranty files.
Peace of Mind – Proven performance from factory to installation.
Learn More About Our Certified Products
We’re proud to provide tested, documented performance across our full range of timber sash windows, casement windows, and doors.
If you’re specifying products for a listed building or conservation area, our Conservation Area Guide explains how certification supports compliance with local authority planning conditions.
You can also explore our Vacuum Glazing Guide for advanced glass performance data.
FAQ's
Q: What U-Values do your windows achieve?
Our timber sash and casement windows achieve U-Values as low as 1.3 W/m²K, verified by UKAS-accredited testing bodies.
Q:Are your doors PAS 24 certified?
Yes. Our timber entrance and French doors are tested to PAS 24:2022 standards, confirming resistance to mechanical attack and forced entry.
Q: Can I request a copy of your test reports?
Of course. Please contact us, and we’ll provide the relevant certificates for your chosen window or door type.
Get in touch today
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If you have any questions or would simply like some more information about our high performance timber windows & doors, then simply fill in the form below and we will be in touch.
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