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Home > About BWF > Total Support Services > Basic U-Value Calculations (ECWINS)

Basic U-Value Calculations (ECWINS)

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From 1 October 2010, window manufacturers in England and Wales will need to be able to demonstrate that their windows comply with the energy efficiency requirements in the latest 2010 revision of Part L of the Building Regulations and the Approved Documents L1A (new dwellings) and L1B (existing dwellings).  This is usually done by declaring the windows’ U-value.  In a change from the previous regulations, it is now only possible to comply with the Regulations by declaring the centre pane U-value in certain specific and limited situations.  For the most part, the U-value must relate to the window as manufactured.

Obtaining a precise U-value for a manufactured window can be prohibitively expensive for smaller manufacturers.  The BWF is able to offer this service to its members to provide a basic U-value calculation to enable them to obtain the figure they need to comply with Building Regulations at a reasonable cost.

Furthermore, architects and specifiers are asking increasingly for the thermal transmittance values of windows, so that they can calculate the SAP ratings of the buildings into which the windows are to be fitted.  If you cannot provide U-values, then they may opt to use the windows of a competitor who does have the information to hand.

Download the Information Document here for full details.

NB: This service is for BWF Members only. If you are a member, please ensure you are logged into the site as you will see the application & data information forms below:

 

Part L - Frequently asked questions

Since the launch of the Part L Compliance package for the Basic U-value Calculation (ECWINS) software tool on 2nd August, we have received a considerable volume of data from members for their window ranges. Therefore, to help with understanding some of the intricacies of providing the right data, we thought it would be worthwhile giving some answers to your frequently asked questions concerning compliance with Building Regulations Part L from 1st October 2010. Click here to link to the questions (You need to be logged in to view these)