New Dwellings

New Dwellings

Heath road dwelling

The Part L 2021 clock is ticking.

Through its Future Homes Standard 2019 consultation ending on 7th February 2020 (extended from 10th January), the government has set out its proposed changes to Part L (conservation of fuel and power) and Part F (ventilation) of the Building Regulations for new dwellings.

Major changes to the requirements have been proposed for Part L in 2020 ahead of the introduction of the Future Home Standard in 2025.  For new dwellings, the consultation sets out two options to uplift energy efficiency standards in 2020 and the requirements as follows:


Option Reduction in carbon emissions (compared with current standard)  Anticipated solution 
 1  20%  Very high fabric standards (typically with triple glazing).
 2  31%  Carbon-saving technology such as photovoltaic panels and better fabric standards (though not as high as in option 1).


The government has indicated its preference for option 2.

Proposed changes to the minimum elemental standards for fabric performance – sometimes referred to as 'backstop' values - include reducing (improving) the window U value from 2.0 to 1.6 W/m2K.  However, the expectation is that the U value will have to be much lower than this to enable new dwellings to achieve the whole building minimum energy performance target.  This is highlighted in the impact assessment undertaken on the proposed changes for new homes, which has modelled building specifications based on the following window U values:

   Part L 2013 Part L 2021 Option 1  Part L 2021 Option 2 
 Window U Value (W/m2K)  1.4  0.8  1.2


Documents related to the consultation on proposed requirements for new dwellings can be found here.

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.