Mumford &amp; Wood, the manufacturer of high performance timber windows, French doorsets and entrance doors, is claiming a U-value of 1.4 for single or double, fully glazed doors in the Conservation range of period-style products. <br> <br> This measurement is within the new Building Regulations Part L specification which requires a minimum U-value of 1.8 for glazed and panelled timber doors. <br> <br> Casement and sliding sashes in the Conservation range are fully compliant with the new legislation already. Mumford &amp; Wood’s standard casement has a BSI energy rating of B, with an overall frame U-value of 1.4, while the Eco alternative specification casements and sashes already satisfy the 2016 energy and carbon reduction improvement targets.<br> <br>