The Government has initiated a consultation concerning changes to the Building Regulations for existing dwellings in England. These changes are expected to have a significant impact on glass and glazing products in residential buildings.
Ending on 13th
April 2021, the consultation set outs proposed changes to Part L (conservation of fuel and power) of the Building Regulations for existing dwellings in England. This follows on from last year's consultation on new dwellings, the Government's response to which has been published
. Ventilation and mitigating overheating in new dwellings are also included in the same consultation.
For replacement windows, doors and rooflights in existing dwellings, the following standards have been proposed:
|Window or roof window
|WER Band B or better, or
U value 1.4 W/m2K
|U value 2.2 W/m2K
|Doors with greater than 60% on internal
|Door Set Energy Rating (DSER) Band C, or
U value of 1.4 W/m2K
|Door Set Energy Rating (DSER) Band B, or
U value of 1.4 W/m2K
For windows, the above is an improvement on the current standard of WER Band C or U value of 1.6 W/m2K
WER, Window Energy Rating, is generally considered a better indicator of the energy performance of a window because it considers a range of parameters, including the useful solar heat gain. The U value is the total U value of the window, taking into account both the glass and frame.
The U value of a rooflight should be based on the outer developed surface area, which is often greater than the area of the roof opening.
The proposals include an alternative if windows or fully glazed external pedestrian doors cannot meet the above requirements because of the need to maintain the character of the building. In such cases, they should achieve or better a centre pane U value of 1.2 W/m2K or be upgraded to low emissivity (low-e) secondary glazing.
To satisfy the above requirements, Pilkington provides a range of low-e glass that can provide thermal insulation.
Documents related to the consultation on proposed requirements for existing dwellings can be found here.
If you have any questions on Part L 2021 and what the implications might be for glass, please complete our online contact form, selecting 'Architect' or 'Trade' as the Enquiry Type and 'Part L 2021' as the Nature of Your Enquiry.