CIBSE updates guidance on assessing overheating risk in homes

The Chartered Institution of Building Services Engineers (CIBSE), in partnership with Arup and Loughborough University, has published an updated version of its CIBSE TM59 guidance. This revised publication provides industry professionals with enhanced methodologies for assessing and addressing the risk of overheating in new residential buildings and major refurbishments.

CIBSE TM59, a key industry resource referenced in Part O of the UK Building Regulations concerning overheating, has been updated to incorporate the latest research and practical experience. The revisions reflect the evolving understanding of how homes can be designed for comfort and resilience in a warming climate. Overheating is a growing concern in the UK's residential sector, with many homes vulnerable due to factors such as extensive glazing and inadequate ventilation.

The updated guidance emphasizes the importance of passive design strategies early in the development process. A key enhancement requires all homes to be assessed under unconstrained conditions using future weather files representing the 2050s climate. This approach aims to ensure buildings can maintain comfortable internal temperatures without relying on energy-intensive cooling systems.

Specific improvements include new approaches to assessing bedroom overheating, informed by recent research from Loughborough University. The guidance also incorporates revised recommendations for the use of ceiling fans as an effective, low-energy measure to improve occupant comfort. CIBSE anticipates the updated TM59 will improve the consistency of overheating assessments and support the delivery of climate-resilient, energy-efficient homes.