AES Sustainability has recently completed a comprehensive programme of retrofit improvements for Cambridge Housing Society (CHS), delivering end to end retrofit assessment, air testing and coordination across 118 homes.
The project formed part of a wider strategic review, which began with AES conducting an assessment of CHS’s portfolio of around 3,000 homes. AES and property and construction consultancy McBains identified 15 distinct archetypes that helped shape the client’s long-term approach to asset improvement. AES also supported CHS with a funding application that successfully secured just under £1 million towards the delivery of retrofit works.
Many of the oldest properties were pre-1930 solid wall homes, with some featuring 1970s cavity wall extensions. Others were 1990s cavity wall construction. A small number of low rise flats were also included. Before retrofit activity commenced, AES undertook a detailed series of assessments to establish a reliable baseline. This included air tightness testing, borescope inspections, property typology verification, occupant surveys and the collection of technical evidence required for pre-improvement EPCs. These investigations helped inform a fabric-first approach designed to achieve an EPC rating of at least C.
CO-ORDINATING WORKS ON SITE Delivery of the retrofit measures required close collaboration between AES and the primary contractor, Aran Insulation. AES provided on-site coordination throughout the project, overseeing that the sequencing of works was compliant with PAS2035, acting as liaison between contractor and the client and ensuring that residents remained informed and supported at every stage.
AES’s Retrofit assessors, coordinators and advisors were regularly present on site, offering the practical, day to day oversight required to maintain quality, resolve issues quickly and keep the programme moving efficiently. AES also helped to manage the resident queries and feedback that came via CHS’s Asset Management team, providing the human connection that frequently becomes the first and last point of contact for households undergoing retrofit works.
The measures installed across the 118 homes reflected their differing construction types and needs. Solid wall properties received external wall insulation (EWI) while homes with cavity walls benefited from new cavity wall insulation. Where appropriate improved ventilation and new windows and doors were also fitted, alongside loft and flat roof insulation. Several off-grid homes received modern high heat retention storage heaters, while solar PV was installed on selected properties with suitable roof conditions.
One Cambridge property has provided a particularly clear illustration of the impact achieved. Following AES’s assessment and design recommendations, the home was upgraded with new windows and doors, EWI, new loft insulation and improved ventilation. The resident commented that she “couldn’t believe the difference” the measures had made, emphasising both the improved comfort and the visual transformation of her home. Similar feedback was received across the programme, with residents consistently reporting positive experiences linked to AES’s on site presence and communication.
The AES team completed full post retrofit assessments, air tightness testing, photographic and technical evidence gathering, and responses to audit requests, ensuring full PAS compliance and providing CHS with a clear, transparent record of the improvements delivered.
By managing every phase – from initial portfolio analysis and funding support through assessment, design, coordination, resident engagement, contractor liaison and final compliance – AES has delivered a retrofit that improved energy performance, reduced costs and enhanced comfort for households across the region.
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