The purpose of this circular letter is to draw attention to the publication of the following:

• updated Notice of approval of the methodologies of calculation of the energy performance of new buildings to demonstrate compliance with the Building Regulations 2010 in England
• updated Notice of approval of the methodologies for expressing the energy performance of buildings in England and Wales

The new notices of approval supersede the existing versions and come into effect on 17 March 2025. Please see the circular for full details.