New and existing domestic buildings

New and existing domestic buildings

Pilkington Thermal Efficiency glass
Through its consultation ending on 26th November 2021, the Scottish Government has set out its proposed changes to Section 6 (Energy) of the Technical Handbooks for domestic and non-domestic buildings.

For new domestic buildings, the consultation sets out two options to uplift energy efficiency standards in 2022 as follows:
Option  Reduction in carbon emissions (compared with 2015 standard)  Anticipated solution 
32% Improved fabric standard and waste water heat recovery
57% Triple glazing and mechanical ventilation with heat recovery

There are proposed changes to the maximum U values for fabric elements for new domestic buildings.  However, the expectation is that the U value will have to be much lower than this to enable new dwellings to achieve the Target Primary Energy Rating (TPER).  The notional building specification used to determine the TPER is based on the following U values of fenestration elements:
Element U value (W/m2K)
Option 1
Option 2
Doors 1.2 1.0 
Windows 1.2 0.8
Roof windows 1.5 1.0
Rooflights 1.7 1.3

The maximum U value for fenestration elements of dwellings (including extensions and existing dwellings) are summarised below:


U value (W/m2K)
Option 1
Option 2
Windows and doors 1.4 1.2 
Rooflights 1,9  1.7 

  1. U values for rooflights should be calculated on the horizontal plane
  2. The proposals do not refer to Window Energy Ratings
The consultation documents can be found here.

If you have any questions on changes and what the implications might be for glass, please complete our online contact form, selecting 'Architect' or 'Trade' as the Nature of Enquiry and 'Other' as the Enquiry Type. Please state 'Technical Handbook Section 6' in the Question / Comment box when completing the form.