BuildCheck Website Window/Door U Value calculations
There are two routes to producing U-Value calculations for windows and doors offered by BuildCheck.
- UKAS accredited calculations, in line with BS EN ISO 10077-1:2017. This a bespoke calculation for the specific window/door and will produce a calculation which can be incorporated into, for example, Declaration of Performance, (DoP) for a UKCA marking, (formally CE Mark) application and certification with such bodies as CERTASS and FENSA
- Using our online 'Oracle' tool to simulate U-value calculations using build ups from a predefined library of components. Thus, enabling fabricators and installers to produce calculations for use for Building Regulation compliance and guidance.
This method uses predefined elements from various manufacturers and cannot address specific elements and materials.
Once you have registered your Oracle Account you can then have access to a great range of features and tools:
- Create your Quality Control System (FCP) - Use the simple Oracle Factory Production Control (FCP) template and Guide.
- Recognised by FENSA and Certass, The U Value Calculator will check the thermal, acoustic and product performance of your windows & door sets with the Oracle U Value Calculator
- Make sure your Products have Initial Type Testing - Follow the Oracle UKCA Mark check list to ensure your products have valid Initial Type Testing (TT).
- Complete a Declaration of Performance for your products - Use the Straightforward Oracle Declaration of Performance (DOP) template and guide.
- Apply a UKCA Mark to your products - Use the Oracle UKCA Mark template and guide.

U-Value Calculator
Calculations from the Oracle online U-value calculator are recognised by FENSA and Certass for their competent person schemes. Once subscribed, it’s quick and easy to assess product performance and is pre-loaded with product data for many popular window and door set suites from major PVCu window system companies.
Window Energy Ratings – the Oracle U-value calculator can help find the right glass and frame combination for your WERs.

Acoustic Calculator
The Acoustic Calculator on the Oracle is a cost-effective alternative to acoustic labelling and testing schemes. It enables subscribers to the Oracle to quickly calculate the acoustic performance of a range of frame and glazing options and in most cases, with no need for acoustic testing in a laboratory.
Subscribers can then have the calculations verified with a report from an accredited UKAS-notified body such as Build Check Limited. We are a UKAS-accredited testing laboratory body No. 4044.

Registered for your Oracle Account today and gain access to our online calculator
