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Building Regulations Part O, for Overheating, applies to all residential buildings and came into effect in England on 15th June 2022. Its reach is extensive covering dwellings, care homes, student accommodation and halls of residence, boarding schools and residential colleges.

Part O’s stated aim is to protect the health and welfare of occupants by reducing the occurrence of high indoor temperatures. See our other articles on implications of Part O on building design.  There has been additional statutory guidance in the form of a frequently asked questions (FAQ) document following Part O’s release. The FAQ document provides further clarity on applying Part O, for instance it includes:

  • Clarifications on how far a development must take passive measures before resorting to active cooling when using the dynamic method;
  • Whether some window opening can be allowed in bedrooms where there are some external noise constraints during the night; and
  • Confirmation on how to calculate equivalent and free areas of windows for the simplified method (where contradicting information was provided within Part O).