This project is a powerful collaboration between energy experts Severn Wye and ALMO Cheltenham Borough Homes (CBH), which is responsible for the management and maintenance of Cheltenham Borough Council’s (CBC) housing stock. These organisations worked together to improve the energy efficiency of 59 of the Council’s homes and improve the health and comfort of their tenants. This project was a ‘first’ for Cheltenham in that it involved fabric improvements at scale and the use of a new technology (ground source heat pumps) for the Council’s housing stock.
Severn Wye was contracted to provide retrofit assessment, coordination and evaluation (in compliance with PAS 2035:2019+A1:2022 retrofit standard, the best-practice approach for retrofit improvement works) for 59 properties on behalf of CBH.
The Social Housing Decarbonisation Fund (SHDF) aims to improve the energy performance of social homes in England. A main requirement for the project was to achieve an EPC C rating of all properties, reduce their heat demand. Our retrofit coordinators made sure all the works specified would meet stringent technical energy efficiency standards of PAS2035 – a necessary requirement to access SHDF grants towards the installations.
CBH also wanted to improve the comfort of its tenants, reduce their heating costs, and reduce the occurrence of condensation, damp and mould in their properties. Twenty-five properties at Cummings Court, mainly purpose-built retirement flats, had failed cavity wall insulation removed and a new bonded bead system installed. Poorly controlled electric underfloor heating systems were replaced by a new ground source heat pump on shared ground loops – a first for CBH. All the flats benefitted from new high-performing double glazing and loft insulation in all top-floor flats.
A second group of 34 homes, Wimpey No Fines system builds, were of non-standard 1950s and 1960s construction, mostly in blocks of maisonettes. These all received 110mm mineral wool external wall insulation. The top-floor flats had 400mm of loft insulation installed, and flat roof insulation on any exposed bays.
Essential for retrofit, all properties had upgraded ventilation to improve internal air quality and mitigate damp, mould and condensation.
After the energy efficiency measures were installed Severn Wye completed an EPC on each property and calculated the heat demand. The project achieved or exceeded its intended outcomes and made significant savings for the properties; all reached EPC C with an average of C75; one property achieved an EPC of B84. All but two properties achieved energy for heat demands below 90 kWh[e]/m2 a year.
Total savings of £40.1k per annum were identified, when starting costs are adjusted to inflation. In total carbon savings of 83.7 tonnes a year were identified, totalling lifetime savings of 3,200 tonnes. Energy savings were made of an estimated 259,775.8 kWh per annum (based on SAP primary energy use).
Resident feedback was 84% positive, and all the responses identified that measures were performing as expected. No unintended consequences were identified – a huge positive for the project. Important lessons were learnt about the processes involved in larger scale retrofit. This will help support the next stage of works on further properties.
In total 120 energy efficiency measures were installed using £800k grant funding from the Social Housing Decarbonisation Fund (SHDF) Wave 1 and £600k funding from Cheltenham Borough Council’s housing revenue account.
