Existing Dwellings

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 energiKare™ in a dwelling
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.