CIBSE AWARDS | BUILDING PERFORMANCE CHAMPION GETTING REAL WITH RETROFITS To meet its net zero targets, the UK has to get to grips with carbon emissions in its ageing houses, and fast. The Welsh School of Architectures retrofit programme is doing just that and its pioneering work was recognised last month when it was named CIBSEs 2023 Building Performance Champion. Andy Pearson reports R etrofitting existing housing stock for energy efficiency is one the UKs most challenging issues. It is a topic that the Low Carbon Built Environment (LCBE) team, Welsh School of Architecture (WSA), Cardiff University, has been grappling with over the past 12 years through a series of projects. Now, working together with Wales and West Housing (WWH) and other social housing and local authorities, the WSA has delivered a series of whole-house retrofits across South and West Wales that demonstrate that by adopting a systematic approach it is possible to use off-the-shelf systems to significantly reduce the energy consumption and improve occupant comfort. Savings vary depending on original heating system, condition of the home and occupancy among other things. Net operational carbon has fallen by up to 95% with a reduction in residents energy bills of 75% and beyond where residents are conscious of their behaviour. Its approach clearly impressed the judges at this years CIBSE Building Performance Awards, where the WSA won the Collaboration category and the coveted Champion of Champions award. The judges described the entry as an exemplar project demonstrating true collaboration with multiple stakeholders on a challenging retrofit, and said learnings from this collaboration will have far-reaching impacts in Wales and beyond. A key aspect of the project is that it builds on WSAs learning from earlier retrofit projects, including the Technology Strategy Boards Retrofit for the Future programme in 2009, when the School applied its whole-house approach to retrofitting a 1980s urban end-of-terrace house. Whole-house energy systems are about considering the house holistically, rather than focusing on individual elements, says Professor Joanne Patterson, Professorial Research Fellow at WSA. Alongside its retrofit research, the WSA has applied its whole-house 20 April 2023 www.cibsejournal.com approach to new builds. Completed in 2015 and targeted at social landlords, the Solcer House claimed to be the first affordable energy-positive house built in the UK. At the same time, the WSA started its retrofit collaboration with WWH, on a project supported by the Welsh European Funding Office to deliver whole-house energy systems in 10 representative homes. We wanted to get as close to zero carbon as we could while keeping costs down, by optimising the use of low carbon technologies in each of the homes, says Patterson. It was this collaboration that formed the basis of the WSAs awards entry. Properties retrofitted were in need of major refurbishment. We tried to choose a range of homes of various ages and types to deliver a suite of outcomes, but the push factor for refurbishment in each case was that either the propertys boiler or roof was nearing the end of its life and was in need of replacement, Patterson explains. Driven by data Success for the whole-house energy systems approach depends on informed, data-driven decision-making. The starting point is a survey of each home using the WSAs Practical Retrofit Early Stage Survey tool (Press). This is a structured data-collection spreadsheet, designed for use by non-experts. It is intended to help speed up and formalise accurate data collection. The School developed the survey specifically for the domestic sector through its work with social housing providers. A brief initial survey is carried out on each of the homes, and the pre-retrofit questionnaire is used to help understand how residents use their homes