BWF Launches U-Value Calculation Service for Members

The 2010 revision of Part L of the Building Regulations and the Approved Documents for new and existing dwellings, which come into force in England and Wales in October 2010, will require manufacturers of windows to declare the windows’ U-value.  It is no longer possible to comply with the Regulations by declaring the centre pane value provided by the glass manufacturer.  The U-value must relate to the window as manufactured. Obtaining a U-value for a window can be prohibitively expensive for smaller manufacturers. The BWF has launched a ‘Basic U-value Calculation’ Service to its members to enable you to obtain the figure they need to comply with Building Regulations for the reasonable cost of £95 (plus VAT). We are able to carry out a window U-value calculation based on the British Standard ‘BS EN ISO 10077-1:2006 Thermal performance of windows, doors and shutters. Calculation of thermal transmittance. General.’ using the ECWINS software tool, which is only available through the BWF and only to BWF members. You submit the relevant data for the window to us.  We will then calculate the U-value using the ECWINS software, and issue you with a certificate in accordance with that standard, which can be used as formal support when you supply U-value information to potential customers or Building Control Bodies (BCB). The U-value calculated is sufficient to satisfy the requirements of Building Regulations, but is not as precise as a full U-value simulation.  It cannot be used as the basis for obtaining a full BFRC Window  Energy Rating (WER nor could it be submitted as if it were a WER. A U-value for an energy rating needs to be simulated to Part 2 of BS EN ISO 10077.   The BWF offers other Total Support Service packages which can help you obtain full U-value simulations or Window Energy Ratings. The link to the ‘Basic U-values Calculation’ service is a feature of our Part L Compliance package and can be found here.