Part L1b Area Weighted U-Value app for iPhone and iPad

For domestic extensions which are heavily glazed (in excess of 25% of the extension floor area), you are required to prove that the proposals will perform no worse than the ‘notional’ dwelling with the maximum allowable glazed area. Our App provides the calculations to prove that your extension falls within the allowable limits, or whether your extension complies though improved area weighted u-values.

The App allows data input for the extension envelope, with designed areas and u-values. The App will use this data to compare the designed extension with a ‘notional’ extension to indicate compliance via the 2 calculations. The first calculation will determine whether the area of glazing complies with the allowable area, whilst the second calculation will determine compliance through an area weighted u-value comparison to the ‘notional’ extension.

Following the input of data, and the calculations within the App, a report is developed to confirm compliance, and a link is email-able to download the calculation report free of charge.