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:

• Window, roof window or rooflight: Window Energy Rating (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

The 2021 edition of Approved Document L Volume 1 2021 was published on 15^th December 2021 for implementation from 15^th June 2022. It introduces changes for existing dwellings, including the requirements for replacement windows and doors.

The following standards have been introduced for windows and doors:

• Window (including roof window or curtain walling): U-value of 1.4 W/m²K or minimum WER Band B
• Rooflight: U-value of 2.2 W/m²K
• Doors with greater than 60% on internal face glazed: U-value of 1.4 W/m²K or minimum Door Set Energy Rating (DSER) Band C
• Other doors: U-value of 1.4 W/m²K or minimum DSER Band B

For more information on the requirements for existing dwellings in Approved Document L Volume 1 2021 edition, please click here.