Part O 2021: Overheating

Part O 2021: Overheating

A new Building Regulation, Part O, has been introduced and will be effective from 15th June 2022.

All residential buildings as noted below will now be subject to an overheating assessment which must be submitted to Building Control.

  • Dwellings – both Houses and Flats
  • Care Homes
  • Student Accommodation
  • Residential college
  • Hall of residence
  • Shared communal rooms/common spaces in blocks of Flats, Student Accommodation etc..

Overheating will need to be taken into account early on in the design process in order to demonstrate compliance with Part O via one of the following methods:

  1. Simplified Method:

This method is suitable for dwellings only (houses and flats), any other type of residential building must follow the ‘Dynamic Thermal Modelling’ method below. This will also be applicable for any dwelling that does not demonstrate compliance via the ‘simplified method’.


  1. Dynamic Thermal Modelling:

 More complex thermal modelling based on CIBSE TM59 guide.

For further information on the new Part O Building Regulation, please contact us for your free copy of our ‘Part O in Detail’ PDF document.

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