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What is the Part O Building Regulation?
Part O of the Building Regulations (Overheating) was introduced in June 2022 to address rising indoor temperatures caused by improved airtightness, climate change, and increased use of glazing in modern homes. It applies to new residential buildings in England, including houses, flats, and residential institutions such as care homes.
Part O aims to reduce overheating risk by requiring building designs that maintain safe indoor temperatures without relying excessively on air conditioning.
What Part O specifies:
Maximum glazing areas and orientation limits to control solar gains.
Cross-ventilation requirements to promote passive cooling.
Shading measures such as blinds, overhangs, or external shading devices.
Simplified and dynamic compliance routes using either the “simplified method” (for straightforward designs) or “dynamic thermal modelling” (for complex buildings).
Security considerations to ensure that ventilation methods (like openable windows) remain safe for occupants.
