Energy Efficiency Standards for Building Conversions
The government has retained current MCU energy efficiency standards for now, but plans further consultation on uplifted requirements. Home User Guides are now required for MCU dwellings.
Current Standards Retained
The government has decided to retain current limiting standards for MCU dwellings rather than introduce whole-building performance targets at this stage. While 84.5% of consultation respondents supported whole-building standards, significant concerns were raised about practical achievability given the diversity of MCU buildings. Current elemental standards ensure a minimum level of performance for individual fabric elements.
Home User Guides Now Required
Approved Document L has been updated to clarify that Home User Guides should be provided to owners of dwellings created through MCU. This brings MCU dwellings in line with new-build requirements, ensuring that occupants receive information about how to operate their heating, ventilation, and hot water systems effectively.
Further Consultation Planned
The government will undertake a further consultation on MCU energy efficiency standards, including: an optional whole-dwelling performance target alongside a stronger elemental standard, reviewing which building conversion types MCU standards apply to (particularly HMOs and temporary accommodation), reviewing circumstances for relaxation, and applying BREL reports and airtightness testing to MCU buildings.
Why Not Uplift Now?
Despite strong consultation support, the lack of clear consensus on specific proposals — combined with concerns about heritage buildings, diverse building types, and practical achievability — led the government to defer uplifted standards. Many respondents who selected "Yes" in the consultation did so with significant caveats, indicating support for change in principle but not for the specific proposals presented.