Existing Dwellings
The Part L 2021 consultation process has commenced with proposals being released for new dwellings. The corresponding proposals have yet to be issued for existing dwellings, but we are expecting major changes to the requirements for replacement windows and doors.
The consultation on proposed changes for existing dwellings are anticipated in accordance with the following timeline:
| Date |
Action |
| Late 2020 / early 2021 |
Consultation on energy efficiency standards for work carried out in existing dwellings |
| Early / mid 2021 |
Publication of new Part L, Part F and overheating regulations |
| Mid / late 2021 |
Part L, Part F and overheating regulations come into force |
The requirements for replacement windows and doors (referred to as controlled fittings) in the current version of Approved Document L1B for existing dwellings are summarised below:
| Controlled fitting |
Standard |
| Window, roof window or rooflight |
WER Band C or better, or
U value 1.6 W/m2K |
| Doors with >60% of internal face glazed |
Door Set Energy Rating (DSER) Band E, or
U value of 1.8 W/m2K |
| Other doors |
DSER Band E or better |
Window Energy Rating (WER) which 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 or door, taking into account both the glass and frame.
Pilkington provides a range of products that can provide thermal insulation.
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.