Guest post: insulate Britain or miss net zero

Jack Marley, The Conversation

The UK is failing to enact the policies that would put it on track to reach net zero emissions by 2050, according to a progress report by the Climate Change Committee. The head of this expert body, which advises the government on its climate strategy, described the UK’s record on home insulation in particular as “a complete tale of woe”.

Gas heating in draughty homes is one of the country’s biggest sources of carbon emissions – and a leading cause of poor health and poverty as energy prices remain sky-high. So what would it take to turn this around?

“The transition to net zero emissions is often framed as a race to make new stuff – such as electric vehicles and wind turbines – as fast as possible,” says Ran Boydell, a visiting lecturer in sustainable development at Heriot-Watt University.

“That’s actually the easy part. The hard part will be modifying what already exists – and that includes people’s homes.”

Cavity wall insulation, triple-glazed windows, solar panels, low-carbon heating systems such as heat pumps which run on electricity: all of these things and potentially more are needed to neutralise the contributions to climate change made by 26 million homes (the number of existing homes Boydell anticipates will still be around in 2050). That would eliminate 68 million tonnes of CO₂, which is about 15% of the national total.

“The idea is to ensure that no home emits greenhouse gases by burning fossil fuels for energy and that, eventually, each home could produce as much energy as it uses,” Boydell says.

According to analysis by the Climate Change Committee, the average cost of retrofitting a single home to net zero standard is £26,000. Energy savings would make up for this after 20 years, but most households would struggle to make such a big upfront investment.

“Considering energy efficiency measures purely in terms of financial payback will never stack up,” Boydell says. “They must be considered in terms of carbon payback. Carbon payback is how quickly the reduced carbon emissions from daily life in a net zero home take to make up for the carbon emissions that went into making and building all the different parts.”

A home operating at net zero standard would compensate for the carbon that went into building it after just six years, Boydell estimates. But it’s the responsibility of the government – and not individual homeowners – to juggle these considerations, he says.

“Infrastructure, like roads and railways, is the only stuff people build which counts its payback periods in decades. The government needs to think of a mass retrofit programme for our houses in those terms: as critical national infrastructure.”

Fund, regulate and overhaul

Matthew Hannon and Donal Brown study green policy at the universities of Strathclyde and Sussex. They say that:

“At an absolute minimum, the government should be aiming to install insulation in 1.3 million homes a year – a rate it managed pre-2013.”

To reach that level, Hannon and Brown have four suggestions. First, increase annual funding for retrofitting homes from £1 billion to £7 billion – enough to retrofit 7 million homes by 2025, they claim. Next, shift the burden of raising this money into general taxation and away from energy bill levies which strain the poorest households and inflate the cost of heating homes with zero-carbon electricity.

Insulating hundreds of homes at a time, neighbourhood by neighbourhood and coordinated by local authorities, could help to retrofit housing deeper and faster than tackling homes one by one,” they say. For this, collaboration with local groups and businesses who know the community well will be key. Hannon and Brown argue the government will also need a separate, well-funded programme to install heat pumps and other low-carbon heating systems, while phasing out support for gas boilers.

An engineer adjusts the external fan unit of a heat pump on the side of a house.
Heat pumps, if powered by renewable electricity, can decarbonise heating. I AM NIKOM/Shutterstock

Once a national campaign to renovate Britain’s homes to net zero standard is underway, there are certain to be teething problems. The Labour Party offered a comprehensive programme of home insulation at the 2019 election. At the time, Jo Richardson, a professor of housing and social inclusion at De Montfort University, and David Coley, a professor of low-carbon design at the University of Bath, described the obstacles that will need to be overcome.

“The UK construction sector is highly fragmented – and different subcontractors are often responsible for the walls, roof and electricity in a single house. This makes quality control difficult. There’s also a skills shortage, especially when it comes to the detailed knowledge required to build a zero-energy house. And if energy-consuming extras such as underfloor heating or electrically driven windows are added, the energy savings from design may be lost,” they say.

The Climate Change Committee noted that new homes are rarely net zero standard, with 1.5 million built in recent years that will need to be retrofitted. The preferred solution for Richardson and Coley is to mandate each new home to Passivhaus standard, which certifies that it produces as much energy as it uses.

“Passivhaus only works if the right design decisions are made from day one,” they caution. “If an architect starts by drawing a large window for example, then the energy loss from it might well be so great that any amount of insulation elsewhere can’t offset it. Architects don’t often welcome this intrusion of physics into the world of art.”

Increased funding, new regulations and an overhaul of architectural norms will be necessary to roll out zero-energy homes and retrofit existing ones. “That’s a tall order,” say Richardson and Coley. “But decarbonising each component of society will take nothing short of a revolution.”

Jack Marley, Environment + Energy Editor, The Conversation

This article is republished from The Conversation under a Creative Commons licence. Read the original article.

Further reading: more on energy efficiency from The Knowledge Exchange blog

Is this the future of social housing?

Goldsmith Street: Mikhail Riches / Tim Crocker 2019

Last year, a development of 105 homes on the outskirts of Norwich became the first social housing project to win the prestigious Royal Institute of British Architects Stirling Prize.

The Goldsmith Street estate was built by London architecture firm Mikhail Riches for Norwich City Council, and is the largest Passivhaus scheme in the UK. Passivhaus is an approach to building that provides a high level of occupant comfort while using very little energy for heating and cooling.

Goldsmith Street has been carefully thought through, and adjusted to take account of changing economic and environmental circumstances. In 2008, Norwich City Council selected Mikhail Riches to design the estate. The council had intended to sell the site to a local housing provider, but when the financial crash happened, the council decided to develop the site itself.

The architects have striven to ensure that the development acknowledges the historic context of the site:

“The design seeks to re-introduce streets and houses in an area of the city which is otherwise dominated by 20th century blocks of flats… Street widths are intentionally narrow at 14m, emulating the 19th century model.”

The homes themselves have been built to strict Passivhaus standards which include:

  • very high levels of insulation;
  • extremely high performance windows with insulated frames;
  • airtight building fabric;
  • ‘thermal bridge free’ construction;
  • a mechanical ventilation system with highly efficient heat recovery.

Passivhaus standards typically reduce heating energy consumption by up to 90% as compared to traditional housing. For residents in the Goldsmith Street development, heating bills should be about £150 a year.

Eco friendly housing

In recent years, local authorities and housing associations have been responding to the increasing demands for housing stock to have lower maintenance costs, lower energy costs and fewer emissions of carbon and other gases that can be harmful to the environment and human health.

The Passivhaus Trust has highlighted a growing number of local councils and housing associations that have been exploring Passivhaus standards as a way of tackling these issues.

One of the most ambitious social housing Passivhaus projects is Agar Grove in the London Borough of Camden. Previously a 1960s estate with an unenviable reputation, Agar Grove has been rebuilt with affordable and energy efficient homes. The first phase, involving 38 social rented homes was completed in 2018, and has already won awards for sustainability and community consultation. Once complete, the 500-home estate will be the largest Passivhaus development in the UK.

Cunningham House, Glasgow: Page\Park Architects

In Glasgow, the city’s first Passivhaus development for social rent was opened by Shettleston Housing Association in September 2019. The project provides nineteen new homes for older people in an innovative design that combines a five storey Passivhaus tower with a converted church building. All of the homes benefit from high levels of thermal insulation to augment the sandstone coat of the existing church structure. The project was named the best affordable housing development at the 2019 Inside Housing Awards.

Meanwhile, the City of York Council has released plans to build more than 600 homes across eight sites over the next five years that will be built to carbon zero standards. The council has pledged that 40% of the homes will be affordable, with 20% retained for social renting. The developments, also designed by Mikhail Riches, will have very high energy efficiency standards that exceed standard Passivhaus levels. It’s predicted that residents’ heating bills could be around £60 a year.

Homes for the future

There is a now a growing sense that housing, as well as consuming great amounts of energy, can also be a positive force for change. Energy efficient homes can make a strong contribution to climate change adaptation measures, can make housing more resilient to increasingly common extreme weather events, and can provide opportunities to improve economic development, quality of life and social equality.

In the past year, with many local councils, combined authorities, devolved administrations and the UK government declaring ‘climate emergencies’, the pressure on housing providers to lead by example has intensified. At the same time, governments are setting out plans to ensure new homes are more energy efficient.

The Ministry of Housing, Communities and Local Government is currently consulting on the Future Homes Standard, which includes proposals to increase energy efficiency requirements for new homes from 2025. Similarly, the Scottish Government plans to introduce new regulations to ensure all new homes use renewable or low carbon heating from 2024. A 2019 report commissioned by the Welsh Government has recommended major changes to most homes in the country, including a major programme to improve insulation and heating.

Goldsmith Street: Mikhail Riches / Tim Crocker 2019

The success and widespread publicity enjoyed by the Goldsmith Street project is likely to encourage other local authorities and housing associations to explore the possibilities of Passivhaus. But although the benefits are great, Passivhaus also presents significant challenges for housing providers.

Up-front costs are higher for Passivhaus developments, and there are additional maintenance and replacement costs. The technical requirements are strict, in order to ensure the maximum levels of airtightness and insulation. In addition, there is a shortage of skills needed to achieve the exceptional standards of construction demanded by Passivhaus (Norwich City Council has overcome this by bringing together a network of specialist contractors with the necessary expertise to work on Passivhaus projects).

Despite the challenges, Passivhaus seems to be offering a compelling answer to the significant problems of fuel poverty, climate change and the demand for high quality, affordable housing. As more local authorities and housing associations demonstrate its affordability, Passivhaus is breaking away from its image as a resource for the privileged and moving into the mainstream of social housing.


Further reading: blog posts from The Knowledge Exchange on energy efficiency at home

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PassivHaus … a home for all seasons?

Passivhaus

Image by Pichler Haus, released under a standard Creative Commons Licence

By James Carson

This week, eight contenders are waiting expectantly for the results of the 2015 UK PassivHaus Awards. The awards celebrate sustainability and good building design, with the focus on the PassivHaus concept.

What is PassivHaus?

PassivHaus is an approach to building that is designed to eliminate the need for traditional central heating systems by combining:

  • excellent levels of insulation
  • passive solar gains and internal heat sources
  • excellent level of airtightness
  • good indoor air quality, provided by a whole house mechanical ventilation system with highly efficient heat recovery.

Since its small beginnings as a German-Swedish collaboration in the 1980s, over 30,000 buildings around the world have been built using the PassivHaus approach.

The benefits of PassivHaus

Energy efficiency lies at the heart of a PassivHaus building. The PassivHaus Institut, which plays a leading role in promoting the concept, has claimed that these buildings can achieve energy savings of up to 75% compared to average new builds.  PassivHaus proponents also claim that the buildings have significantly better levels of air quality, and greatly reduce carbon emissions.

Practical issues

While the long-term energy savings are impressive, PassivHaus buildings are not without their critics. Among their concerns:

  • Cost: The higher standards of PassivHaus buildings, including triple-glazed windows, mechanical ventilation systems and vacuum insulation, all add to the costs of PassivHaus construction. The consensus seems to be that PassivHaus will increase build costs by 15% to 25%, and it’s believed that the higher costs have limited the concept’s application to a handful of private housing developments in the UK.
  • Construction time: Because of the optimum performance demanded of them, PassivHaus buildings can take longer to install. In the Republic of Ireland, concerns about slower construction times during a serious housing shortage has prompted the government to oppose plans by local authorities in Dublin to make the PassivHaus standard mandatory for new homes.  PassivHaus proponents in Ireland have condemned the moves as short-sighted, and claim that PassivHauses won’t slow down construction.
  • Adaptability: Another criticism of the PassivHaus concept is that it’s not readily adaptable, and that structural alterations may interfere with the integrity of a PassivHaus building.

A building or a lifestyle?

There have also been claims that residents may themselves have to adapt to PassivHaus living.

“Building a house to this standard means agreeing to live a certain lifestyle, which if lived to the book can work very well, and has been proven to do so time and time again. You must appreciate, however, that building such a home is a lot of trouble to go to if ultimately you do not want to live the PassivHaus lifestyle.” (The Green Home)

However, PassivHaus supporters dismiss the idea that these buildings are too complicated to maintain:

“The ventilation system, not common in conventional buildings, is user-friendly and easy to operate with fewer controls than a normal television.” 

PassivHaus in the UK

The PassivHaus concept was slow to take off in Britain, but more and more UK architects have become interested in PassivHaus since 2013, when the government committed to implementing zero carbon homes from 2016. The zero carbon homes standard will require house builders to decrease all carbon emissions from energy arising from fixed heating and lighting, hot water and other fixed building services, such as ventilation, in new homes. It’s worth noting, however, that the zero carbon standard is less strict than PassivHaus.

The PassivHaus approach is not limited to residential properties. Among the buildings shortlisted for the UK PassivHaus awards this year are a primary school, an office and an education centre.

Elsewhere, the University of Leicester’s Centre for Medicine is currently under construction, and is set to be the UK’s largest PassivHaus building. It’s estimated that the high levels of insulation and a state-of-the-art heating, cooling and ventilation system will reduce the university’s energy bill for its new teaching and research facility by 80%, compared to the previous building.

PassivHaus may also be able to contribute to alleviating Britain’s housing crisis. A social housing project currently under construction in Rainham, east London, aims to demonstrate that PassivHaus is a commercially viable solution to the UK’s shortage of affordable homes. The builders of the 51-home project claim that this will be the first PassivHaus development to be let entirely at affordable rents.

Future prospects

Inadequate heating, poor insulation and high energy costs have become significant factors in the rise of fuel poverty among households in the UK. At the same time, there is a pressing need to reduce dependence on fossil fuels. So, it may be that the buildings being showcased at this year’s PassivHaus awards may come to be seen as ahead of their time.


The Idox Information Service can give you access to a wealth of further information on housing; to find out more on how to become a member, contact us.

Further reading*

 Footprint: three Passivhaus projects, IN Architects’ Journal

Lancaster co-housing (a Passivhaus development), IN Products in Practice

First look: only way is social for Essex Passivhaus homes (energy efficient social housing), IN Property Week

Keeping cosy in Rainham (affordable housing scheme built to Passivhaus standards), IN RIBA Journal

Lessons from Germany’s Passivhaus experience 

*Some resources may only be available to members of the Idox Information Service