Net zero in housing

• Project name: Isle of Arran Energy Efficiency Improvements
• Lead organisation: Trust Housing Association

Statement of support

Trust Housing Association is a leading provider of affordable housing across Scotland, committed to delivering high quality homes and services that enhance the lives of their customers. Trust’s expertise includes energy management, procurement, retrofit, remodelling and driving high energy efficiency standards, all underpinned by a strong commitment to sustainability and long-term net zero goals.

As the Isle of Arran’s largest social housing provider, with almost 300 homes, Trust has been making a significant impact on the island’s energy efficiency landscape over 2024/25. The Isle of Arran is off-gas grid and islanders are disproportionately affected by higher energy costs and fuel poverty, due to the lack of access to the natural gas network. Heating sources have historically been more expensive on the island, predominantly electric or oil-heating. 

In summer 2024, a transformative retrofit programme was launched across their Arran stock, with over £3 million worth of investment upgrades across 252 homes on the Island, 60 per cent of which were classified as ‘hard-to-treat’. Delivered in partnership with Ayrshire-based ‘Green Home Systems’ (GHS), following extensive retrofit assessments on each home, the projects multi-measure improvements included the following upgrades:

• Underfloor, loft, and room-in-roof insulation 
• High Heatetention Storage Heaters 
• Solar PV systems 
• External battery storage for every home 
• Air Source Heat Pumps 
• New ventilation systems.

The success of Trust Housing Association’s energy efficiency programme on the Isle of Arran has been made possible through a strong, values-driven partnership with industry leader GHS. Trust and GHS share the commitment to tackling fuel poverty and delivering sustainable, high-quality housing solutions.

All 252 homes have been upgraded to EPC band B’s from starting bands of D-F. The estimated overall carbon emissions savings from the works are 171tCO2e and the estimated annual energy bills saving is in excess of £225,000 per annum, helping Trust reduce its overall carbon footprint and help its customers reduce bills and improve thermal comfort all year round. Trust, through their partnership with GHS has leveraged in substantial ECO4 Funding to deliver this this project, avoiding the need to pass costs onto tenants and promoting a just transition to net zero. The works on Arran were complemented by fabric improvements during 2024/25 of new PVC-U windows and doors to 91 homes across the villages of Brodick, Lamlash, Shiskine, Corrie and Kilmory.

Ms Galloway, a Trust Housing Association customer, had solar panels and a battery storage system installed in her home in July 2024 as part of the Isle of Arran energy efficiency programme. She had already noticed a positive impact on her energy usage and bills when speaking to us in March 2025, noting, “The monetary savings have been seen in my energy bills already, even though we are in the winter months. However, I am really looking forward to the summer months where we can see the extra savings in energy with the brighter days.”

Trust is committed to delivering high-quality, energy-efficient solutions and to that end, GHS, is accredited by: 

• TrustMark 
• Quality Mark 
• MCS 
• PAS 2035:2023. 

These accreditations and where required, certifications, ensure that all works meet the highest standards of safety, quality, and sustainability.

Trust’s holistic approach - combining environmental responsibility with social care - makes them a standout nominee for this ‘Net Zero in Housing’ award. 

Outcomes and achievements

Upgrading the EPC bands of 252 rural homes to band B, in addition to providing some of their most disadvantaged customers with immediate energy bill savings, has been an outstanding achievement. 

The programme of works has generated £76,000 in contractual community benefits, which have been reinvested into their Hardship Fund, which supports customers across Scotland facing financial difficulties due to the cost of living crisis. The fund provides assistance with essentials such as food, utility bills, and household expenses. This initiative exemplifies Trust’s commitment to social impact - leveraging infrastructure investment to deliver direct financial aid to those most in need. 

The Arran works are already proving a benefit to customers, making their homes warmer and easier to heat. The feedback has been incredible and, as a result, Trust are keen to extend the benefits to as many customers as possible. Building on the success of the Arran project, plans for a further phase of works with GHS across 298 homes in the North and West of the country are progressing and the team at Trust have been sharing their experiences and approaches with several other RSL partners, many of which are only at the beginning of their decarbonisation journey.

• Project name: Pappert
• Lead organisation: West Dunbartonshire Council
• Partner organisations: CCG (Scotland) and MAST Architects

Statement of support

Location

Pappert is a development of 26 homes for social rent in Bonhill, West Dunbartonshire. The 1.36ha site is bounded immediately to the north, south, and east by existing two-storey residential houses. A child’s informal play area and football pitch are located on the northeast/ east boundary, while the site is within close reach of a regular bus route and amenities in Alexandria town centre - including Alexandria Train Station (1.3 miles), ALDI (1.5 miles) – and local schools (Lennox PS, one mile), leisure facilities and places of worship. 

Layout

The site was formerly occupied by tenement flats but after they were demolished, it lay dormant for a significant period, becoming an area of dense vegetation except for a network of footpaths that connected to the surrounding terraces. The biggest challenge to the design and construction of the development was the topography, with a 20 metre level difference falling from east to west. This challenge was also recognised as an opportunity, with the ability to provide excellent views of the neighbouring hills. Several of the existing pedestrian routes were also retained, and new connections formed to ensure wider community integration. 

The housing mix of two-storey terraced homes reflects the surrounding architectural context, while their style and configuration respond to localised housing needs, particularly those of families:

• One bed/two person cottage flat (six)
• Two bed/three person wheelchair accessible cottage flat (three)
• Three bed/five person houses (nine)
• Four bed/six person house (four)
• Four bed/seven person house (one).

All homes have access to their own garden space. Parking is 100 per cent across the one to three bedroom house types, with 200 per cent provision for the four-bedroom property. Each home has an EV charging point.

Design

All of the homes are designed to comply with Housing for Varying Needs, Secure by Design, and with West Dunbartonshire’s Housing Design standard. They range from 65sqm to 138sqm with the aim of maximising tenancy flexibility and enabling future adaption. This includes a ground-floor double-bedroom in each home, as well as barrier free level access. 

Ample integrated storage, and sprinklers are among the features that offer support and improved safety for each residence.

Through direct appointment to the contract, CCG was involved in the design process at the early stages of development. This “early contractor involvement” approach utilises CCG’s in-house technical and divisional expertise and helped to identify any potential risks and delays to project delivery. Undertaken on an open-book basis with the council alongside the contractor-appointed design team, any identified issues were carefully managed while relevant opportunities for value creation and driving overall project costs down (without compromising quality) were highlighted and implemented timeously. The process was made easier through an already existing, long-term relationship with the council which has been in place since 2019 across eight developments, and contributed greatly to realising their sustainability ambitions. 

Net zero and Passivhaus 

Of the 26 homes, 20 have been constructed to the CCG’s net zero home build standard (compliant with Gold Aspect 1 and 2 and equivalent to Platinum Aspect 1 of Scottish Building Regs), and six are Passivhaus Classic-accredited – the first of their kind in the local authority. All homes place emphasis on a fabric first approach, with enhanced airtightness (including thermal-bridge-free design for the Passiv plots) achieved through use of CCG’s offsite-manufactured iQ Timber System, triple-glazed PVCu windows, and enhanced door sets to drastically minimise heat loss. Air-source heat pumps are in place to provide space heating and hot water services. The net zero homes have the added benefit of solar battery storage units. The units connect to between nine and 12 solar panels, and store energy for later use, with the benefit of cheaper evening energy tariffs. 

Outcomes and achievements

CCG used sustainable materials and zero-waste manufacturing processes to deliver these new homes, lowering embodied carbon emissions. Then, through a combination of fabric performance and zero-emissions technologies, operational carbon emissions have been significantly reduced, with an annual energy demand for space heating ranging from 1.69 to 24.13kWH/m2, and Low or Zero Carbon Generating Technologies (LZCGT) abatement, on average, 103.58 per cent across the development. A max EPC rating of 105 (A), and Environmental Impact Rating of 101 (A) has been achieved, with operational energy costs from as little as £35pcm. This means that carbon emissions have been significantly reduced at each stage of the development’s delivery, as well as throughout its lifetime.

Tenants in the immediate term will significantly benefit from lower energy costs, while the council have homes that are future-proofed to changes in building legislation, as well as a real-time comparison of varying building standards, which will help to inform the future of affordable housebuilding in the region as the country embarks upon its transition to net zero by 2045.