The government announced changes to ‘Approved Document L - Conservation of fuel and power’
in December 2021, which will come into force on 15th June 2022.

These changes are in response to The Future Homes Standard consultation in 2020, and The Future
Buildings Standard in 2021. There are further changes expected in 2025 with the ultimate aim to
help the UK deliver ‘net zero’ by reducing carbon emissions from new homes and other buildings by
around 30% in this first phase, and approx. 75% in 2025.

There are transitional arrangements in place which mean that ‘if a building notice, initial notice, or full
plans for building work are submitted to a local authority before 15 June 2022, then provided the building
work commences by 15 June 2023, work on that individual building is permitted to continue under the
previous standards.’ Please note that some projects, such as domestic replacements, would not normally
have required the above notifications, so will need to comply from date of regulation change.

Approved Document L is published in two volumes, Volume 1: Dwellings, and Volume 2: Buildings
other than dwellings: -

The table below highlights the existing and forthcoming limiting U-values: -

Please note that these are ‘limiting’ or maximum allowed values, and in some instances improved figures will be requested to meet the overall buildings target energy efficiency requirements.  This enables flexibility in design of the building.  For instance, it may be difficult or uneconomical to improve on a limiting u-value for a given building element, and better to make improvement on other building elements to hit the overall building target.

There are a number of exemptions/relaxations to the above requirements.

For existing dwellings (Doc L: Volume 1) or existing buildings other than dwellings (Doc L: Volume 2), where windows or fully glazed external pedestrian doors cannot meet the requirements because of the need to maintain the character of the building either of the following should be met: -

a) These fittings should not exceed a centre pane U-value of 1.2W/(m2K)
b) Single glazing should be supplemented with low-emissivity secondary glazing

For new or existing buildings other than dwellings (Doc L: Volume 2), no maximum U-value is set for ‘display windows or similar glazing’.  There are no limits on the design of display windows and similar glazing, but for new buildings their impact must be taken into account in the calculation of primary energy and CO2 emissions.

A display window is defined as: -

‘an area of glazing, including doors, to display products or services on offer to the public within a building, positioned as in all of the following.

  • At the external perimeter of the building.
  • At an access level.
  • Immediately adjacent to a pedestrian thoroughfare.

If there is a permanent workspace within one glazing height of the window, this cannot be considered as a display window.  Glazing more than 3m above an access level should not be considered part of a display window, except where the following applies.

  • The products on display require a greater height of glazing.
  • Building work involves changes to the façade and glazing that require planning consent, and planning requirements mean that a greater height of glazing is necessary, e.g. to fit with surrounding buildings or to match the character of the existing façade.

Approved Document F – Ventilation & Approved Document O - Overheating

There are also changes to Approved Document F - Ventilation, with changes to the requirements of background ventilation with impact on use and sizing of trickle vents, and an entirely new Approved Document O – Overheating which covers overheating mitigation requirements for new residential buildings only.

Information on all of the above, including links to these revised approved documents, can be found on the link below: -

For further information, please contact the Kestrel Technical Department on 0121 3333575.