Retrofit Explainer
The UK Government has committed to make the UK carbon zero by 2050. UK emissions are split roughly into thirds between buildings, transportation and industry. Of the emissions associated with buildings, the majority relates to existing building stock, both domestic and commercial. 80% of the buildings that will produce emissions in 2050 already exist, and are unaffected by stricter targets for Building Regulations as these only affect new buildings.
The Part L regulations are weak by comparison to our European neighbours and groups like LETI, RIBA and AECB all recommend we should already be building to 2030 levels of energy efficiency or we are simply adding to the pile of buildings that will need a retrofit before 2050.
LETI definitions of Deep vs Shallow retrofit
Accepted industry standards target a reduction in energy use of around 60% per dwelling. The key actions are to remove fossil fuels (primarily natural gas) as a fuel source for domestic heating and hot water. These provide around 75% of the energy demands in a typical property. From 2025 no new homes can have a gas boiler fitted. The 60% energy reduction target already factors in the 'greening' of the National Grid through increasing amounts of renewable energy sources.
The Retrofit Challenge facing the UK is huge. The Minimum Energy Efficiency Standard (MEES) requires that rental properties must have an EPC rating of C by 2025, but no legislation exists for transforming private residential. Resources for home owners are poor and the costs of a deep retrofit will run to tens of thousands, be disruptive and may face constraints around planning or listed buildings. The whole process is overwhelming to think about.
LETI graph showing the target range for retrofitting UK housing stock
Local Authority Housing groups have access to government funding schemes like the Social Housing Decarbonisation Fund in order to improve energy efficiency. These mandate the use of PAS 2035, a risk assessment and design management process to ensure that energy efficiency measures are appropriate, designed and installed correctly and crucially, will deliver the intended results. This hopes to address a lack of confidence in the retrofit sector as a result of poorly performing schemes, or those which have adversely affected occupants' health or fuel bills.
A number of tried and tested methodologies for retrofit exist, and all are compatible with PAS 2035. These include EnerPHit (Passivhaus existing buildings standard) and AECB CarbonLite. The RIBA and LETI have published targets for domestic buildings (various typologies) and non-domestic (offices, schools etc.) to give clients and designers an achievable benchmark. Published case studies give working examples and PAS 2035 requires feedback and evaluation to help share data.
LETI table of performance standards for retrofit and new build
With proper dwelling assessments, risk analysis and professional designers, the retrofit process can deliver huge benefits for user comfort, indoor air quality, reduction in bills and emissions. It can help reduce individual fuel poverty and ensure our national fuel security by reducing reliance on both imported energy and fossil fuels. New professional roles (Retrofit Assessor, Retrofit Coordinator, Retrofit Evaluator) are being created to support the delivery of retrofit projects.
