Design & Build

Five hundred homes in Agar Grove in North London are being redeveloped by Camden Council – the project is reported to currently be the largest Passivhaus development in the UK Feature Heading Design & Build

A new era of low carbon and energy-saving dwellings

While the Passivhaus standard for buildings has been around since the 1990s, it is finally beginning to gain traction in UK, with many examples of local authority building projects being constructed to the energy-saving standard

The UK’s built environment is responsible for 25 per cent of the UK’s greenhouse gas emissions. With government targets for the country to be net zero-emission by 2050, more environmentally friendly methods of design and construction are being sought to address the issue, as well as more efficient ways to heat and cool buildings.

Passivhaus is an international design standard, which cuts energy use from buildings and delivers high standards of comfort and health. Developed in Germany in the early 1990s, the design standard uses very little energy for heating and cooling, instead using a ‘whole building’ approach to construction, based on the principle that reducing heating loss to a minimum is the most cost-effective and robust way of achieving a low carbon building. Key passivhaus features include insulation, stringent levels of airtightness, minimal thermal bridging, solar optimisation, and mechanical ventilation with heat recovery.

UK Passivhaus projects

Camden Council is in the process of re-developing 500 homes in North London, known as Agar Grove, which is reported to currently be the largest Passivhaus development in the UK. The project, which won in the Large Projects category of the UK Passivhaus Awards 2021, recently reached a new milestone with the ‘topping out’ of the latest phase of 125 homes. The form of the building is efficient, allowing insulation thicknesses below those conventionally associated with Passivhaus. Achieving the airtightness on this scale is easier in many respects, but much harder to test. To achieve the required levels of airtightness, the construction team undertook the largest ever pressure test of its kind in the UK. The air test took a full day, with eight separate fans and miles of cabling and pressure tubes across the complex shape and layout of the building.

Michelle Christensen from Camden Council said: “We are determined to tackle fuel poverty and reduce CO2 without the need for complex energy systems with high lifetime costs. The Passivhaus approach provides thermal comfort and air quality in a way that alternatives do not match. Although this can increase the initial capital costs, Camden Council – as both developer and landlord – believes that it will see the benefits of this approach, in Passivhaus is an international design standard, which cuts energy use from buildings delivering high standards of comfort and health higher build quality and reduced maintenance costs over the lifetime of the buildings.” Powys County Council has completed a £1.3m development in Sarn, Wales. It was the first social housing to be built for the local authority in 30 years and the first ever to meet Passivhaus conditions. The development was highly commended in the Constructing Excellence in Wales Awards. The seven energy efficient homes – a mix of two-bedroom bungalows and two-bedroom and threebedroom houses used low energy construction methods and included sustainability features such as solar panels and mechanical heat ventilation recovery systems that reduce running costs for tenants. The project also used Welsh-grown wood for the timber frame, while cellulose fibre insulation, manufactured from recycled newspaper, was used to reduce E

We need your help

Millions of people are at risk of the deadly consequences of confl ict in Ukraine.

People are fl eeing their homes and families are being separated. Many are going without food or clean water. We must get critical support to those who need it most, in Ukraine and its bordering countries. Please donate to the DEC Ukraine Humanitarian Appeal, if you can.

Visit redcross.org.uk/shelter or text SHELTER to 70141 to make a £10 donation.

By texting, you consent to future telephone and SMS marketing contact from British Red Cross. Text SHELTER NO to 70141 to give £10 without consenting to calls and texts.*

Keeping in touch Your support makes a life-changing difference to people in crisis. We write to our supporters to update you about the work of the British Red Cross, and how you can help and donate in other ways. You can change the way we contact you at any time by visiting redcross.org.uk/keepingintouch or calling Freephone 0800 2800 491. Privacy statement The British Red Cross is committed to privacy and will use personal data for the purpose it was collected or other legitimate purposes we tell you about: for example, to provide goods, services or information you have requested or to administer donations or services we provide. We may also analyse data we collect to better understand the people who support us or those who use or deliver our services. Sometimes this means us combining that data with information from reliable public sources. Our research allows us to tailor communications and services in a more focused and cost-effective way, as well as better meeting your needs and the needs of others like you. However, we will never do this in a way that intrudes on personal privacy and will not use your data for a purpose that confl icts with previously expressed privacy preferences. For full details about how we use personal data, our legal basis for doing so and your privacy rights, please see our privacy notice online at redcross.org.uk/privacy. The DEC Ukraine Humanitarian Appeal will support people in areas currently affected and those potentially affected in the future by the crisis. In the unlikely event that we raise more money than can be reasonably and effi ciently spent, any surplus funds will be used to help us prepare for and respond to other humanitarian disasters anywhere in the world. For more information visit https://donate. redcross.org.uk/appeal/disaster-fund * Texts cost £10 +1 standard message (we receive 100%). For full T&Cs visit redcross.org.uk/mobile, must be 16+. The British Red Cross Society, incorporated by Royal Charter 1908, is a charity registered in England and Wales (220949), Scotland (SC037738), Isle of Man (0752) and Jersey (430).

London Borough of Hounslow‘s plans for its Convent Way redevelopment includes 900 Passivhaus homes

Passivhaus, net zero and retrofit

An independent organisation that promotes the adoption of Passivhaus in the UK, the Passivhaus Trust celebrated its twelfth anniversary with a hydrid debate on net-zero, retrofit and the latest lowcarbin home developments

E

 plastic. Speaking about the commendation, Powys County Council’s Deputy Leader Cllr Matthew Dorrance said: “This brilliant and ground-breaking development has been built to the exceptionally low-energy Passivhaus standard which will help to cut carbon emissions while tenants will have lower energy bills.”

Meanwhile, the London Borough of Hounslow has submitted plans for building approximately 900 Passivhaus homes, as part of its plans for redeveloping its Convent Way housing estate in Heston.

The 900 homes of the project are aiming for Passivhaus certification. The redevelopment of the estate will help set a new urban dwelling standard for the London Borough of Hounslow integrating Passivhaus design, landscaping, sustainable transport, and building quality.

The project is currently at the pre-planning consultation stage and has yet to receive planning permission.

A spokesperson from the project’s lead architect Bell Phillips Architects, said: “Delivering Passivhaus homes set within new parks, streets and well-connected green infrastructure is a significant and challenging aspiration on such a constrained site. “The design will foster a high quality of life for residents, create a cohesive and safe community and will be highly sustainable in line with zero carbon policies.”

Passivhaus Bill proposed in Scotland

A proposal for a Bill is out for consultation in Scotland which calls for all new housing in Scotland be built to the Passivhaus standard or to a Scottish equivalent. The Bill would apply to every new home built by councils, housing associations or the private sector.

In June 2022 the Scottish Government announced its Building a net zero future strategy for new build homes, outlining its proposals for new building regulations, which aim to ‘cut emissions of all new-build homes by nearly a third’. However, the proposals do not include the Passivhaus standard, which industry professionals say is a tried and tested solution to deliver net-zero-ready homes.

Alex Rowley, MSP for the Mid Scotland and Fife Region, who proposed the Bill, said: “While we welcome the direction the Government are working in, the proposed new standards do not go far enough to tackle inefficient housing and reduce greenhouse gas emissions. They also miss a crucial aspect of our Bill which is the need to close the ‘performance gap’”. He goes onto say “Unless we introduce a verification process for energy efficiency, any changes to building regulations will remain Powys County Council has completed a £1.3m development in Sarn, Wales. It was the first ever to meet Passivhaus conditions inaccurate due to the gap in what an EPC rating suggests a building can achieve in terms of energy efficiency and what it actually achieves. It is a welcome improvement but it does not bring the standard of modelling and testing up to the same standard as Passivhaus quality standards”. Sarah Lewis, Research & Policy Director at the Passivhaus Trust, said: “When many worry about the cost of living and accelerated cost of household energy bills, this proposal could not come at a better time for the country.” The Domestic Building Environmental Standards (Scotland) Bill is out for consultation until 27 July 2022.

Cost of living crisis

With the climate emergency and cost of living crisis impacting our everyday lives, the efforts to create energy efficient buildings is now more pressing than ever. Thanks to the mechanical ventilation and heat recovery system in a Passivhaus designed building, as well as clever design features, only minimal heating is needed to be comfortable to live in. This helps to slash energy bills for occupants and reduce the buildings impact on the environment. While industry is rising to the challenge of energy efficient buildings, Sarah Lewis, Education & Policy Director at the Passivhaus Trust argues that the government needs to do more. She said: “If we are to live within the means of our global system, we need to radically reduce the energy demand of our existing buildings. The industry is beginning to rise to the challenge – but to drive this forward at the scale and speed required, we need clear strategies from Government to set agendas, shape public discourse, and ultimately mandate action.” Indeed, as increasingly more buildings are developed to the Passivhaus standard, and the environmental benefits continue to be recognised, the UK will get closer to achieving its net-zero ambitions. L FURTHER INFORMATION

passivhaustrust.org.uk

Powys County Council’s £1.3m Passivhaus development in Sarn, Wales has seven energy efficient homes that use low energy construction methods and feature solar panels and mechanical heat ventilation recovery systems that reduce running costs for tenants