The Eclipse Leisure Centre in Staines-upon-Thames sets the standard for low-carbon sports and leisure facilities by combining Passivhaus building performance with the latest energy-efficient swimming pool technology.
As the largest wet and dry sports centre of its kind in the UK, Eclipse is projected to use 60% - 70% less energy than comparable buildings.
Passivhaus certification - anticipated in early 2025 - is set to confirm its status as one of the world’s most efficient leisure facilities.
Completed for customer Spelthorne Borough Council in 2024, Eclipse’s super-insulated construction and energy efficient features - including a first-of-its-kind pool ventilation system – are a product of the partnership between Willmott Dixon, GT3 Architects, and Passivhaus experts Gale & Snowden.
To achieve a highly sustainable end product, Eclipse includes:
- Efficient heating and cooling: Heat pumps provide combined heating and cooling, redirecting heat generated in the gym to warm the pool and extracting heat from the pool backwash.
- Stratification ventilation: A stratified ventilation system maintains a higher humidity level closer to the pool, while the air above the water is 10% drier, improving the climate outside the pool, while reducing energy consumption and pollutants.
- Innovative pool design: The swimming pool is virtually chlorine free. It uses a micro-filtration technology with a ceramic plate arrangement and ultra-violet light to filter out contaminants in the water. This creates a much better swimming environment and uses much less energy and water than a typical sand filtration pool.
- World’s first rooflight over a Passivhaus swimming pool: A unique rooflight provides the pool area with natural light, without compromising Passivhaus levels of insulation and airtightness.
- Green roof: A rooftop garden with fruit trees enhances social and environmental well-being.
Compliance with Passivhaus standards remained central at every stage of construction and required close collaboration with the supply chain. The strict protocols and quality control required were overseen by a dedicated Passivhaus manager. Using custom software, the manager collected all the necessary evidence for Passivhaus certification, including over 600 photographs to document the quality of the build.
The Passive House Institute (PHI), in Germany, has praised Willmott Dixon’s thorough approach to quality assurance on the project.
Efforts were made throughout the construction process to minimise environmental impact, including:
- Low-carbon construction materials: The project used low carbon concrete with 70% ground-granulated blast furnace slag (GGBS) in all the foundations. This reduced the embodied carbon of the concrete in the foundations by 212 tonnes or 39%. The use of Cross Laminated Timber (CLT) for internal walls reduced embodied carbon by 1,456 tonnes, the equivalent of recycling 503 tonnes of waste.
- 100% diversion of construction waste from landfill: supporting Willmott Dixon’s Now or Never ambitions to eliminate all avoidable waste from landfill.
- Battery-powered tools: One of the first sites to use battery-powered small tools and cement mixers exclusively.
- Use of HVO fuel: Replaced diesel with hydrotreated vegetable oil (HVO) fuel reducing CO2e emissions by 90% and saving 157 tonnes of CO2e.
- Timber waste reduction: Reuse of 281 pallets delivered to the Eclipse site.
- Tree planting: 500 trees were planted in areas that benefit nature and communities.
Beyond outstanding environmental performance, the Eclipse Leisure Centre project delivered significant social benefits for the community, with an £8.5 million social return on investment - nearly 30% of the project’s total cost.
Eclipse reflects Willmott Dixon’s commitment that all our new buildings and major refurbishments will achieve net zero operational carbon by 2030, part of our sustainability strategy Now or Never. Our Decisive Decade.
In 2024, Willmott Dixon is the UK’s leading Passivhaus contractor (certified non-domestic projects over 1,000m2) with £159m currently in pre-construction.
