City and County of Swansea Council – Gwynfaen (Phases 1 – 3)

Background

Gwynfaen is a pioneering housing project located in Penyrheol, Swansea, currently being developed by Pobl Group Housing Association. Comprising 144 homes, it stands as a model of sustainable living, integrating advanced low-carbon technologies with thoughtful placemaking and community design.

AERIAL PHOTOGRAPH 1

CGI 1

Supported by additional funding from the Welsh Government’s Innovative Housing Programme (IHP) Year 3, Gwynfaen will offer a mix of tenures – including homes for private sale, shared ownership and social rent – thus aiming to provide a home for all members of the community.

The project’s key innovations: –
• Homes as Power Stations (HAPS) design principles: Conserve (Fabric), Generate (Solar PV), Store (Battery), Release (Grid Export).
• Off-site manufactured homes using locally sourced Welsh timber.
• Use of other low-embodied carbon materials.
• Trialling the One-Click LCA – Whole Life Carbon measurement tool.
• Achieving an airtightness of less than 2 with MVHR system.
• Green Infrastructure-led Placemaking.

AERIAL PHOTOGRAPH 2

Design and Sustainability Features
Gwynfaen employs a ‘fabric first’ approach to construction, emphasizing airtightness and enhanced insulation to minimize heat loss. Homes are equipped with photovoltaic panels and expansive glazing on south-facing elevations to maximize solar energy capture, complemented by battery storage systems for energy efficiency. Each residence includes electric vehicle charging points, promoting eco-friendly transportation. Heating and hot water are provided by air source heat pumps, eliminating the need for gas boilers. Mechanical ventilation with heat recovery ensures optimal indoor air quality while further reducing heating demands.

Community and Environmental Integration
The development features a central ‘village green’ and landscaped areas that connect to the Loughor Estuary, fostering a strong sense of community and encouraging outdoor activities. A ‘Community Hub’ will be established in a landmark building next to the village green. Throughout the development, Sustainable Urban Drainage Systems (SUDS) are incorporated to manage water runoff, enhancing the site’s environmental performance, whilst also doubling up as incidental greenspace and places for nature.

MASTERPLAN 1

 

MASTERPLAN 2

Construction and Materials
Utilising a panelised timber frame system, the homes are constructed off-site in a factory located less than 10 miles from site, allowing for rapid assembly and high-quality standards. This method contributes to reduced construction waste and supports local supply chains. The use of Welsh-sourced timber (for the panels and cladding) and other natural materials (such as Woodfibre Insulation) further reduces the carbon footprint associated with construction.

MATERIALS

FACTORY

Energy Efficiency and Cost Savings
The project aims for a 91.3% reduction in residual CO₂ emissions, with predicted energy costs for residents as low as £33 per month. This is achieved through a combination of high thermal efficiency, renewable energy integration, and smart energy management systems.

Development and Funding
Gwynfaen is a collaborative effort between Pobl, Swansea Council and the Welsh Government, with significant funding from the Welsh Government’s Innovative Housing Programme. This partnership underscores a commitment to delivering affordable, sustainable housing solutions.

In summary, the Gwynfaen project exemplifies a forward-thinking approach to housing, blending sustainability, community engagement, and innovative construction techniques to create a model for future residential developments.

STREETSCAPE 1

 

STREETSCAPE 2

Design Standards

• Building Regs Part L 2014
• Wales Placemaking Charter
• Manual for Streets 2
• Sustainable Urban Drainage
• Secured by Design
• DQR 2005 (Note this scheme pre-dated WDQR 2021)

Do you have any other quality targets you are working with?

• Home as Power Stations (HAPS)
• Use of Embodied Carbon Measurement Tool – One Click LCA

Heating measures

• Air source heat pumps (Vaillant and Mitsubishi)
• Low surface temperature radiators (2 zones)

Other energy measures

• Solar Photovoltaic (PV) – Viridian Clearline Fusion
• Battery – Sonnen (Phase 1 and 2, Puredrive/Duracell Phase 3 – 5)
• Mechanical Ventilation and Heat Recovery (MVHR) – Nuaire
• Electric Vehicle (EV) Charging – Rolec

Project learning

Number of House Types
The desire to achieve great placemaking led to an increase in the number of house types at Gwynfaen. Parts of the development required a terraced house type to provide a denser feel in the centre with continuous frontages, whereas along the edges of the site a less dense approach was required. Some house types required a second variant according to whether they were south or north facing with changes in the ground floor plan and fenestration. Finally, the mix of tenures on site required a slightly modified range of homes aimed at the sales market (ensuite bathrooms etc.). In total, there are 23 house types at Gwynfaen, and one of the lessons learned was to reduce this on future projects to achieve the cost/performance benefits of greater standardisation especially with off-site manufacture.

Timber Cladding Detailing
Approximately 50% of the homes at Gwynfaen are clad with Welsh Larch. The original detailing of this involved a ‘tongue and groove’ jointing of Larch planks of approx. 120mm in width. After initial sample panelling the following issues were identified: –

• The Larch cladding contained an unexpected number of ‘knots’, and that many of the knots had fallen out, resulting in holes within the cladding.
• There was a tendency for the planks to ‘cup’, thus losing its flattened nature – and resulting in strain being placed upon the jointing which could lead to future splitting of the material.
• After consultation with WoodKnowledge Wales, a decision was made to switch to Welsh Cedar (less prone to knotting), 100mm wide boards (less prone to cupping) and a ‘half-lap’ jointing method with visible screws (less prone to splitting).

TIMBER CLADDING DETAIL

Home User Guidance
Due to the level of innovation involved in the homes – Pobl have modernised the Home User Guide (HUG) for Gwynfaen with a view to using this as a template for all or low carbon homes going forward. Our HUG includes a short video on each technology in the home – to explain how best to use this to achieve an affordable and desirable outcome. The use of QR Codes in the home fastened to each technology also helps as many of our customers prefer smart phone apps enabled to recognise QR Codes.

Monitoring and Resident Feedback
All the homes for social rent and many of the homes for sale include monitoring equipment which record energy consumption, generation, export and other environmental data.
NOTE: The Performance report and Resident Feedback report for Phases 1, 2 and 3 of Gwynfaen will be available in late 2025. This Case Study will be updated when that information is available.

However, based on numerous interactions with residents during 2024 and 2025, we are aware of several positives and negatives that have been brought to our attention: –

• In Winter 2023/2024 problems occurred with the heating and hot water controls, along with other issues such as the connectivity of the battery. Many residents submitted their energy bills to Pobl, based on a perception that these problems were resulting in higher energy consumption. These cases were quickly investigated and resolved and (where appropriate) compensation offered.
• However, amid this, another trend emerged. Some customers believed their bill to be high whereas they were not. Many customers moved in during autumn 2023 and didn’t set up a direct debit – rather wishing to pay for their consumption at the end of each month. Their false perception was that the bills were too high and there must be a fault with their home.
• The reality is now borne out over the year – where the energy consumption April – September reduces dramatically to the point where energy bills at Gwynfaen are generally between £40 – £90 / month depending on resident preferences.
• Many people have enquired about setting up the Smart Export Guarantee (SEG), which is necessary to enable the export of surplus electricity generated by the Solar PV. Residents are expected to apply for this themselves via their Energy Provider. However, Pobl can do more to assist with the process.
• Some residents have struggled with Setting up Apps for their batteries and heat pumps, leaving them less able to see what’s going on or control the home according to their preferences.
• The conclusion is that Pobl needs to develop more in-house ‘know-how’ to deal with such enquiries, reassure and assist tenants and people who have purchased a home at Gwynafen. We also need to be more proactive in the Home User Guide – advising residents on these specific points.

Key Resident Learnings

• Support with Smart Export Guarantee
• Support with billing in general
• Support with setting up apps”

 

Project innovation

Several key innovations that were brought together at Gwynfaen: –

• HAPS principles: From an energy perspective, the homes were designed around the ‘Homes as Power Stations’ (HAPS) concept.
  • CONSERVE – The fabric was designed to meet an airtightness of 1 and improved U-Values (including triple glazed windows) to offer superior thermal performance.
  • GENERATE – The homes included Solar PV and Air Source Heat Pumps to generate renewable electricity.
  • STORE – All homes include a 10kWh Battery which stores energy from on-site renewables as well as the ability to import energy a low-tariff periods.
  • RELEASE – Excess energy generated and stored can be released back to the grid to lower the household bills.

FABRIC STANDARD

• Off-site manufacture: All homes were designed for off-site manufacture (Category 2 – two-dimensional), based on a range of Structural Insulated Panels (SIPs) that could be manufactured in a factory located less than 10 miles from the site.

 

• Welsh Timber: All SIPs panels and all structural components within the homes were manufactured using timber sourced from within Wales. This was verified through the chain of custody process enabling all components to be traced back to the sawmill and forest. In addition, many of the homes were externally clad using Larch and Cedar sourced from Welsh forests.

 

• Low Embodied Carbon: Several other building components were chosen due to their low embodied carbon content.
  • Wood fibre insulation
  • Triple glazed windows manufactured with 95% timber and 5% recycled aluminium.
  • Foundations: Recycled foam glass (slab) and natural hydraulic lime screed.
  • Lime-based render.
  • ‘Wood Wool’ as a substitute for plasterboard.
  • Locally sourced natural stone slips (Pennant stone from the Swansea Valley).

 

• Green Placemaking: One of our key Visions for Gwynfaen was to create a ‘Place Close to Nature’. We wanted to maximise the health and wellbeing benefits of a place with excellent access to nature, trees and green spaces within the development and walkable routes to the landscapes beyond. From the earliest concept stage, we employed a landscape architect/master planner to prepare a green infrastructure into which the streets, homes and gardens could be introduced.

 

• Community focus: Gwynfaen includes a wide range of house types and a mix of tenures – including open-market sale, shared ownership and homes for social rent. A ‘Community Hub’ will be established at the heart of the development – which will provide opportunities for community and social activities. Combined with the ample provision of walkable routes and open spaces, Gwynafen encourages healthy living and community interaction.

 

• Future Adaptability: 90% of the homes at Gwynfaen have been designed and built with a ‘Warm Roof’ where the insulation is within the roof plane. The roof structure of these homes has also been designed as an ‘Attic Truss’ with strengthened ceilings, ventilation and sprinklers, thus enabling the roof space to be repurposed as living spaces, offices, playrooms in the future. This decision was borne of a desire to build-in future flexibility for residents over the long term.”

Challenges

Warranties/Insurance
A 10 Year Structural Warranty provided by the National House Building Council (NHBC) is key requirement of Pobl’s funders and house purchasers. Due to the Innovation around the use of low carbon materials and components, it was necessary to submit and discuss our proposals for Gwynfaen with the NHBC in 2019. Unfortunately, the NHBC didn’t support several of our original choice of materials and components: –

• Wood Wool – which was not accepted as an alternative to plasterboard due to fire testing concerns.
• Natural Stone slips due to the absence of any fire testing of this material when used as part of an external wall system.
• Recycled foam glass (slab) and natural hydraulic lime screed were not accepted due to the higher risk associated with the substructure – should issues occur over the next 10 years.
• It was therefore necessary to revert to the more conventional choice of materials in each case, as neither the time available for securing IHP funding or the resources available for testing permitted further dialogue.

 

LESSONS LEARNED

Mortgage Ability
When homes in the first phases came up for sale – we discovered that none of the main mortgage providers (banks and building societies) were prepared to offer a mortgage on those homes which were clad with Welsh Larch or Cedar. Their standard format for assessing homes – used by 3 local surveyors – raised concerns about the longevity of timber-clad homes. Despite some follow up discussions with the surveyors and backs in question – no flexibility was shown and Pobl had to change the external materials of future phases such that all homes for sale were rendered as opposed to timber. This had knock-on effects upon the planning approval (which had to be amended).

Road/Street Adoptions
Green Placemaking plays a central part in the vision for Gwynfaen. Streets and green spaces are designed to bring plants, trees and wildlife closer to the home – the objective being to elevate the sense of wellbeing for people living at Gwynfaen and experiencing the outdoor environment. A ‘non-standard’ approach was therefore applied to street design and other aspects of the public realm – based on urban/rural design principles promoted in Manual for Streets 2 which favours pedestrians and greenspace over vehicles.

This green placemaking approach was strongly supported by the local planning authority and the Design Commission for Wales. However, it was rejected by the local authority’s Highways Adoption Team who refused to adopt the streets unless major changes were made to the design. These changes would have required a fresh planning application – but would have also compromised the overarching vision of a ‘Place Close to Nature’. The works were held up for over 20 months whilst negotiations were held regarding this. To make progress with the homes Pobl eventually (reluctantly) chose not to go for adoption to preserve the design – and Pobl will have to make alternative arrangements to maintain the streets in future.

Airtightness
To reduce heat losses, energy bills and carbon emissions, an airtightness target of 1m3/hr/m2 was set for the homes –In Phase 1 (4 homes) the contractor achieved 2.5-2.7m3/hr/m2 which was well above the target. Working with the contractor to understand what could be done to improve this – it was possible to achieve 1.5m3/hr/m2 on Phase 2 (37 homes). This still falls short of the original target – however we regard this as a major achievement working with a trusted local contractor to deliver energy efficient homes and a benchmark for future projects.

Commissioning (4G signal strength)
Gwynfaen currently has a network signal strength of 4G – but this sometimes reduces to 3G depending upon the network provider. This made it difficult to commission some of the technologies in the home such as batteries – which require a Wi-Fi signal to upload firmware and carry out the set up. Smart technologies need to be set up prior to occupation and therefore require a temporary Wi-Fi facility. This was not anticipated and led to a change in specification for Phases 3, 4 and 5. For future schemes, consideration should be given to installing a Wi-Fi system during construction, possibly at 2nd fix stage.

Health and Safety
Gwynfaen includes a ‘Nature Area’ along the western edge of the development. This incorporates two attenuation ponds that form part of the Sustainable Urban Drainage solution (SUDs) for the site but also provide an area for plant and animal species as well as areas that can be explored by residents. The design was relatively low-key, allowing access to the area via boarded walkways and paths. However, during the design process, health and safety concerns have come to the fore and the ponds are likely to be enclosed by fencing.