Welsh Housing Awards 2025
Read all the shortlisted entries into this award category, sustainability in housing, at the Welsh Housing Awards (WHA) 2025 and find out who won the award on the night.
The housing sector, like many others, is faced with the challenge of cutting carbon emissions to achieve Welsh government’s net zero targets by 2050. This award recognises organisations that can demonstrate they have overcome some of the significant challenges in cutting carbon emissions.
This award was sponsored by Blake Morgan.
Winning project name
Llwyn Aethnen – A Cardiff Living Project
Winning organisation
Wates Residential
Statement of support
Llwyn Aethnen is the largest project to date in Cardiff Council and Wates’s 1,500 home partnership, Cardiff Living. It has been designed to be net zero carbon ready and is the evolution of earlier projects which were designed to be a 17 per cent improvement on 2014 Building Regulations.
The creation of sustainable, connected and inclusive communities is central to the whole Cardiff Living programme. Cardiff and Wates saw a real opportunity at Llwyn Aethnen to develop this strategy at scale.
The design brief was to create a sustainable tenure blind, intergenerational community including community living apartments for the elderly, affordable rent, low-cost home ownership and housing for sale. This vison has been achieved along with a comprehensive Green Infrastructure strategy which is central to the design concept. The landscaping scheme introduces significant green spaces and additional trees while preserving and enhancing the existing habitat. SUD’s has been integrated into the landscaping producing rain gardens, detention ponds and swales forming new wetland features and a linear park. The strategy incorporates:
- Enhancing and creating green corridors and wildlife linkages
Landscaping enhancing biodiversity - SUDS, biodiversity and landscaping integrated, providing multifunction spaces to encourage wildlife, increasing amenity, biodiversity value and encouraging social interaction
- Wetland environments
- Bat and bird boxes
- Lighting scheme designed around green corridors
- Management strategy to manage and maintain ecological features.
The project is a brownfield development of 149 houses for sale, 21 houses for affordable rent/LCHO and 44 elderly person apartments, part of Cardiff’s Community Living Strategy (Addison House). The affordable homes were funded by Cardiff Council and the open market sale by Wates, developing the site under a development agreement and with an 50/50 overage mechanism on the OMS.
The project was part Innovative Housing Programme grant funded (100 per cent affordable homes, 50 per cent OMS) with six objectives:
- Demonstrate low carbon development at scale
- Demonstrate Demand Side Response (DSR) energy management at scale
- Demonstrate if enhanced sales values can be realised for low energy low carbon homes
- Test bed for Green Mortgage products
- Deliverable and repeatable project not a “concept design pilot”
An exemplar to bridge the “performance gap” - Welsh Government IHP Performance monitoring
- Cardiff Metropolitan University KESS funded research project.
The project is an exemplar in design terms:
- DCFW reviewed
- Although pre SAB the surface water system has been design to be a fully SUD’s compliant
- Green infrastructure and the integration of landscaping, SUD’s and biodiversity central to the design ethos.
A fabric first approach based on Cardiff Living’s previous experience. Low carbon renewable technologies were introduced to supplement this to achieve a net zero carbon ready project. The following energy strategy was adopted:
Houses
- 2.5kw Photo Voltaic Panels (average)
- 5kw battery storage
- Ground Source Heat Pumps
- Smart hot water cylinders
- Oversized radiators
- DMEV.
Addison House
- PV array
- Communal plant/heating/water
- GSHP
- Thermal store
- Battery store
- Underfloor heating
- MEVHR.
Energy performance:
- Best 141 per cent, average SAP 82 per cent improvement on 2014 ADP L
- Houses - EPC A
- Addison House – EPC B.
Cardiff Living partnered with Sero to provide individual Intelligent Energy Systems (IES) to all homes. The controls are based around resident comfort not Kw and allow residents to choose to minimise carbon output or energy costs. Grid management software allows for a DSR to energy management. Stored energy can be used during peak demand periods, surplus energy can be sold back to the grid. DSR can smooth out peaks and troughs in energy demand and generation so reducing the required overall generation capacity. Llwyn Aethnen alone can generate 500kw from the PV panels and can store 1MW of energy. National Grid estimate that every MW of DSR can offset 600 tonnes of carbon.
Outcomes and achievements
At Llwwyn Aethnen we have created a new intergenerational, sustainable community. The development is now a well-established sustainable and cohesive community, integrating different tenure types, generations and nature.
The project set itself ambitious sustainability targets to create a net zero carbon ready project at scale and to demonstrate this through post occupancy evaluation.
Homes were designed to:
- Typical three bed house (estimated)
- Mains energy 4,000kwhrs/yr
- Carbon footprint 550kgC02/yr
- Energy bill £125/month.
POE has demonstrated average energy bills of £97 per month compared to a current new build average of £197 (average for all homes is £242).
Other POE outcomes included
- Humidity levels were below 60 per cent (target 60-40 per cent)
- CO2 levels below 600ppm (target <1,500)
- Internal temperature 21.47 degrees average
Whole Life Carbon and Circular Economy were also undertaken with the following results:
| Life cycle modules | RIBA BAU | Addison House | Houses |
| A-C (excl B6/B7) | <1,200 | 925 | 984 |
| Circular Economy | |||
| Building Circularity Score | 15 per cent | 19 per cent | |
| Recycled Content | 10.48 per cent | 1.61 per cent |
The CE strategy complies with the overarching values of CE.
The homes are set on a journey to net zero carbon ready as the grid continues to decarbonise with a target to be carbon neutral by early 2030’s.
Shortlisted entries
Tirion Homes - Parc Eirin
Application entry
- Project name: Parc Eirin
- Lead organisation: Tirion Homes
- Partner organisations: Pobl Group, Kensa, Morganstone, Synergie, Welsh Government
Statement of support
Parc Eirin is a pioneering low-carbon residential development in South Wales, led by Tirion Homes in partnership with Pobl, Kensa, Morganstone, and the Welsh government. This innovative scheme responds to the Welsh government’s net zero challenge by delivering 114 EPC A-rated homes, each equipped with ground source heat pumps, solar PV panels, battery storage, and intelligent energy management systems.
The development showcases a bold step forward in decarbonising heat, one of the UK’s most pressing sustainability challenges and the move to commercial investment in low-carbon energy infrastructure. Kensa’s innovative shared ground loop infrastructure and Shoebox NX heat pumps enables Parc Eirin to eliminate the need for fossil fuels while offering residents the familiarity of traditional heating systems. SNRG’s micro-grid and smart demand management system complements the renewable energy generation and maximises the aggregated efficiency across the site. This model is subsidy-free and funded by institutional investors, making it scalable and financially viable for future developments. The project’s success has already influenced policy discussions around the Future Homes Standard in Wales and sets a benchmark for future off-gas developments.
The impact on residents has been overwhelmingly positive. Social insights gathered by Cardiff University revealed high satisfaction with thermal comfort, reduced energy bills, and the availability of EV charging points. Residents reported lifestyle changes, including switching to electric vehicles and increased environmental awareness. Monitoring data from phase one homes showed they were 45 per cent more energy efficient than typical new builds, with solar PV generating up to 127 per cent of annual energy demand in some cases. The transition from Sero Life to Octopus Energy in 2024 further empowered residents with greater control over their energy systems, responding directly to user feedback and enhancing engagement.
Parc Eirin exemplifies sustainable collaboration. It brings together housing developers, energy providers, technology innovators, and government bodies to provide a pathway to commercially viable low carbon communities of the future. Technology plays a central role in Parc Eirin’s success with Mixergy smart cylinders that learn hot water usage patterns, Sonnen communal batteries and Resideo thermostats, equipping each home with systems that optimise energy use and reduce costs. The Intelligent Energy System (IES) initially provided centralised control, and its evolution reflects the project’s responsiveness to resident needs.
Testimonials from key partners underscore the project’s significance:
- Tamsin Lishman, CEO at Kensa: “Parc Eirin is a flagship initiative showing how we can deliver game-changing renewable heating at scale.”
- Alex Brierley, co-head at Octopus Energy Generation: “This project shows how we can do things differently – harnessing proven technology to deliver clean, affordable warmth from the ground up.”
- Jayne Bryant, cabinet secretary for Housing and Local Government: “The homes at Parc Eirin will be climate-friendly and future-proof – a fantastic example of how the ground source heat pump network can be both innovative and commercially viable.”
Parc Eirin is not just a development, it’s a blueprint for the future of sustainable housing in Wales and beyond.
Outcomes and achievements
Parc Eirin has successfully delivered 111 low-carbon homes, with the second phase of a further 114 due for completion by the end of 2027. All homes achieve EPC A ratings and feature ground source heat pumps, solar PV, battery storage, and EV charging points.
Energy performance monitoring from phase one homes showed they are 45 per cent more efficient than typical new builds, with solar PV generating an average of 67 per cent of annual energy demand. The best-performing homes generated 127 per cent of their energy needs.
Social research revealed high resident satisfaction with comfort, energy savings, and support services. The transition to Octopus Energy in 2024 improved user control and engagement with home energy systems.
Parc Eirin has demonstrated a scalable, investor-backed model for renewable heating and electricity, influencing policy and setting a precedent for future developments. It stands as a leading example of how innovation, collaboration, and resident-focused design can drive sustainability in housing.
