Buntingford First School: England’s first net zero carbon passivhaus school

Built to Passivhaus standards, targeting low embodied carbon materials Buntingford First School opened its doors in September 2023 as the first net-zero carbon school in the UK, resulting in ultra-low energy buildings, promoting environmental sustainability.

Appointed by Morgan Sindall, and Hertfordshire County Council Rolton provided multi-disciplinary engineering services including civil, structural and building services (MEP) engineering.

The building is arranged over two storeys, comprising 10 classrooms (including a rooftop outdoor classroom), nursery and play areas for 330 pupils. With sustainability at its core, the project provided savings on operating costs and a reduction in carbon emissions featuring over 300 solar panels, 6 EV charging points, air source heat pumps and triple glazed windows.

Aligned with Hertfordshire County Council’s ambitions to be carbon neutral by 2030, the school was designed with carbon reduction in mind and built to Passivhaus Standards and has achieved Passivhaus Plus, meaning thermal energy consumption is typically 90% lower, and gas and electricity consumption typically 70% lower, than a standard new building, resulting in significant savings on operating costs and reduced carbon footprint.

During design stages, our engineers rationalised drainage, foundation designs and structural elements to help reduce embodied carbon. The number of piles in the foundation solution was reduced by around 20% and internal ground beam widths reduced where possible, resulting in less material required in construction.

• Net zero carbon in both construction and operation – the first wholly NZC in England
• Exceeded the embodied carbon target of 600kg of CO2 per square metre set by the Low Energy Transformation Initiative (LETI) – by 50%
• Surpassing an airtightness target of 0.6 ach (0.25 ach)
• The low carbon cross laminated timber (CLT) frame used provides durability while reducing the carbon footprint of the external structure by around 80% when compared against a more traditional concrete frame solution
• The CLT frame significantly reduced the build sequence for the main structure down to approx. three weeks, instead of the six months typically expected with traditional build methods
• The building features triple-glazed windows, air source heat pumps for heating and hot water, and over 300 solar panels which will power electric vehicle charging points. All teaching spaces face north, without south-facing windows that could cause rooms to over-heat, while the “social functions” of the school face south
• Our civil engineers worked closely with Hertfordshire County Council to agree the drainage strategy and a plastic paving grid was used instead of concrete. Our structural engineers used concrete as sparingly as possible and avoided traditional floor slabs, instead using a pre-cast suspended hollow core plank system to reduce the volume of concrete used, resulting in further carbon savings.

Credit for photography: Hertfordshire County Council and Morgan Sindall.