Question to the Ministry of Housing, Communities and Local Government:

To ask His Majesty's Government what plans they have to incorporate references to (1) solar gain and (2) solar shading, in the design requirements for new-build homes in order to mitigate the effects of overheating.

Part O of the Building Regulations was introduced in 2021 to reduce the risk of overheating in new residential buildings . Part O came into effect in June 2022. This means that new residential buildings must now be designed in such a way as to reduce overheating. This requirement is met by designing and constructing the building to limit unwanted solar gains in summer (including through shading) and by providing an adequate means of removing excess heat.

In existing residential buildings, insulation measures can help reduce risks of overheating, if correctly installed and with adequate ventilation. This is why all energy efficiency measures installed under current government funded schemes require installers to be Trustmark registered and measures must also be installed in accordance with the Publicly Available Specification (PAS) 2030 and PAS 2035 standards, protecting the consumer against poor workmanship. PAS 2035/2030 requires a whole house approach to home retrofit projects and ensures that the risks of unintended consequences, such as mould and condensation due to poor ventilation, are minimised.

We are also considering the issues surrounding overheating in homes created through a material change of use (i.e. homes created by converting another building type, such as an office block) and whether changes to the Building Regulations are appropriate. We intend to consult on our approach to overheating in these homes as part of our consultation on the Future Homes Standard.

Details of further work to determine risk and guide interventions related to overheating, including in existing homes, is set out in the Third National Adaptation Programme (NAP3) report, published in July 2023.