CIBSE AWARDS | BUILDING PERFORMANCE CHAMPION A benefit of the residents remaining in place is that they become embedded in the process by engaging with those carrying out the work, which gives them a sense of ownership of the installation Using this assessment, the WSA and WWH produced a series of options. We sat with the residents and said weve got these suites of choices: this one costs more but the carbon performance is better, or this option has lower running costs, which enabled us, as a team, to make a decision on which options to go for based on the type of occupant. It is this process of considering each property individually that makes the work of the WSA applicable to domestic retrofits nationally, says Patterson. It is the thinking process rather than the actual solutions that is relevant, she says. The first retrofit carried out under the project was of a two-storey, pitched-roof, solid-wall, three-bedroom, end-of-terrace house orientated to face east-west. Completed in 2018, the works included: the addition of internal insulation on the stone-front faade, with external insulation applied to the gable and rear wall; loft insulation; a new roof incorporating building-integrated photovoltaic panels; battery energy storage; and a MVHR system (see diagram below). The homes existing gas heating system was retained as it was relatively new. The project demonstrated that PV panels could be used effectively in Wales on east- and west-facing pitched roofs, although the panels on this home were found to be oversized and generated more energy than required by the home for most of the year. It would have been advantageous to install an electric heating system to use the excess electricity. Unusually, the retrofit also included a transpired solar collector on the south-facing gable wall. This proved to be effective at pre-heating the MVHR supply air; however, as a one-off; it was expensive and Patterson says the technology would be better suited to new-build projects, which would benefit from economies of scale. Another lesson learned was the importance of having a construction manager to oversee the programme of works, because they provided a single point of contact for the residents, contractors and the social landlord, and they understood how the various interventions were interconnected. A significant issue for social housing providers is the need for occupants to remain in the properties throughout the works. Generally, social landlords are unable to decant residents because it is costly, disruptive and requires a property to be vacant for their relocation, explains Patterson. As a compromise, the works were undertaken in two phases for some properties. Although residents might grumble, she says the benefit of this approach is that they become embedded in the process by engaging with those carrying out the work, which gives them a sense of ownership of the installation. Unless people are engaged, they dont understand why the work is being undertaken, which is important for the ongoing operation. Another benefit of the residents remaining in place is that they can see and experience the benefits of the interventions as they happen. The WSA obtained feedback from residents after completion of the works, and is continuing to do so on an annual basis. In addition, the School is in the process of interviewing the supply chain to get its feedback on the project. To ensure correct operation of the systems, residents are provided with a simple, non-technical user guide developed by WSA after spending time talking to occupants about their concerns in operating the retrofitted technologies. Solar inverter The first retrofit was a twostorey, three-bedroom, end-of-terrace house Lithium battery Mechanical ventilation heat recovery Building integrated PV panels Supply Transpired solar collector External wall insulation EPS board Glass fibre mesh Key coat Finishing coat Extract Internal wall insulation Plasterboard EPS board Front Rear 22 April 2023 www.cibsejournal.com