As of 2022/2023 some key parts of the building regulations have been updated to attempt to reduce the operational energy consumption of buildings. Part F (ventilation), Part L (fabric performance) and the new Part O (overheating risk) are most important to understand the shift in performance parameters.

Part F, Part L and Part O

Part F – Ventilation

Part F has been simplified in part to take account of greater levels of energy efficiency and airtightness in new-buildings. The key changes are that, where mechanical ventilation is required, there will also be robust whole dwelling ventilation (eg. Via trickle vents) and a means of providing purge ventilation (opening windows to allow water vapour of excessive heat to escape).  Alternative scenarios such as MVHR and passive stack ventilation are still viable, but may also require dynamic modelling to demonstrate compliance with the new Part O requirements to limit overheating. 

Part L – Fabric Performance

Fabric Efficiency standards are being overhauled to set a minimum U-value requirements in all project scenarios.  For example, for domestic projects it will no longer be possible to offset a reduced fabric performance with other parameters in SAP.  Although the fabric changes are currently a relatively small step for new-build properties, further improvements are likely to come into force in 2025 and therefore it is extremely important to have effective strategies for embracing the higher performance floors, walls, windows and roofs!  Stickland wright have a suite in in house skills and tools to allow us to carry out u-value calculations to ensure that projects are surpassing the new requirements

The Department for Levelling Up, Homes and Communities (DLUHC) announced the changes in Building Regulations 15th June 2022. These changes are part of the roadmap to the 2025 Future Homes Standard. 

Part O – Overheating Risk

The new part O section of the building regulations has been brought in to tackle the risk of overheating in better insulated and airtight buildings.  This has been broken down into two routes for compliance:  the simplified method – for more conventional projects  or dynamic thermal modelling – for more complex projects or buildings where there may be larger glazing areas and there is a real risk of overheating in the summer months.    Stickland Wright have developed specialist in house tools for addressing the simplified overheating calculations and have also acquired the expertise to carry out dynamic thermal modelling and comfort assessments using IES 3D environmental software.