What next for energy efficient homes?

York XIII-OK

Guest post, by Dr Alina Congreve, Centre for Cities, University of Hertfordshire, and
Dr Dan Greenwood, University of Westminster

The controversy surrounding the scrapping of the zero carbon target for new homes continues, despite its removal by the government in July 2015. The House of Commons Energy and Climate Change Select Committee report, published in March 2016, was highly critical of the government’s approach to energy efficiency and housing. There has also been a strong reaction to the closure of the Zero Carbon Hub at the end of March. The Hub was widely regarded as an exemplary model of collaboration between government, industry and third sector.

Critics of the government’s approach to new housing policy point out that the initial drivers behind the zero carbon target have not gone away. European requirements that all new buildings are ‘nearly zero’ energy by 2021 are still in place. The Climate Change Act requires a fall in emissions of 80% by 2050 (from a 2006 baseline). Given the limits to reduction from retrofitting existing buildings, emissions reductions from new build need to be even higher.

There is a widespread view within the sector that the most effective way to achieve energy efficient new homes is through regulation, supported by appropriate tools and training developed in collaboration with the industry. For planners working in local authorities, the options for requiring developers to go beyond the Building Regulations are severely curtailed. Following the Housing Standards Review, they can no longer require developers to build to higher levels of the Code for Sustainable Homes. Influencing new development through stronger regulations was a key part of many cities’ climate action plans.

In spite of this, local authorities are still able to set higher environmental requirements for commercial buildings and insist that developers build to BREEAM standards. When the costs and savings of regulation are calculated by the government the energy savings to office occupants are included in the calculations. However, when the costs of energy standards for new homes are calculated by the government, energy savings for households are not included. The current processes of reviewing policy are based on financial costs and benefits, but value judgements are made about which costs are included. The Housing Standards Review has created a long period of uncertainty for the industry. The transaction costs that result from this uncertainty, such as staff training or product development to meet a new standard that is subsequently withdrawn, are also not included in policy impact financial calculations.

Possible front cover image II

In the short-term, strengthening Building Regulations or modernizing regulatory tools such as the Standard Assessment Procedure (SAP) seem unlikely. Voluntary codes and standards can have an important complementary role to play alongside regulation. Some landowners who wish to go beyond the legal minimum find a benchmark developed by a third party valuable. Current examples can be found in Norwich, where the city council is using a combination of AECB and Passivhaus standards on sites that it owns and are being developed for housing. In the current market for new homes, consumer drivers are relatively weak and buyers and mortgage lenders rarely place a premium on energy efficiency or other sustainable features. There is, however, the potential to do more to change this situation. If a standard adds value to a property by appealing to buyers, then the business case to do more becomes much stronger.


These views are based on a report carried out for the  Royal Institution of Chartered Surveyors (RICS) Trust on the Future for policy and standards for low and zero carbon new homes. The report draws on over 70 interviews with key stakeholders in the industry. It is available free to download.

Alina Congreve is an Associate at the Centre for Cities at the University of Hertfordshire. An experienced sustainability and built environment professional, Alina has specialist expertise in a number of areas, including sustainability and new residential development and resource efficiency in construction.

Read our other blog posts on energy efficient homes:

The Aktivhaus: is this the future of sustainable living?

DEU, Stuttgart, Dokumentation Aufbau Pavillon Wei§enhofsiedlung, Werner Sobek Design GmbH , Fertigstellung: 2014 , DIGITAL 100 MB 8 Bit. - ©Zooey Braun; Veroeffentlichung nur gegen Honorar, Urhebervermerk und Beleg / permission required for reproduction, mention of copyright, complimentary copy, FUER WERBENUTZUNG RUECKSPRACHE ERFORDERLICH!/ PERMISSION REQUIRED FOR ADVERTISING!

Photo reproduced with permission of Werner Sobek Design GmbH , Fertigstellung: ©Zooey Braun

By James Carson

Earlier this year, we looked at a style of building known as Passivhaus, which is playing an important role in creating energy-efficient homes. Now, another concept – the Aktivhaus – is taking this approach even further, graduating from energy-saving to energy-generating homes.

The Aktivhaus concept

Like Passivhaus, the Aktivhaus has its origins in Germany. Stuttgart-based architect Werner Sobek defines Aktivhaus buildings as those which:

  • offset their annual total energy consumption in a sustainable manner;
  • anticipate and react accordingly to relevant changes both inside and outside the house;
  • continuously measure and optimise all energy streams.

Sobek’s idea has been realised in the form of a building called B10. This prototype Aktivhaus – prefabricated offsite and assembled in a single day – is located at the Weissenhof settlement in Stuttgart. It’s an appropriate site for applying a revolutionary concept – in 1927 the Weissenhof estate hosted a housing exhibition that included designs by leading lights in modern architecture, such as Le Corbusier and Ludwig Mies van der Rohe.

The Aktivhaus enacted

On the face of it, B10 is an 85 square-metre box with a full-length window. But its sophisticated design means the Aktivhaus can generate twice as much electric power from sustainable energy sources as it consumes. This means it can not only satisfy its own electricity needs, but can also power two electric cars and a neighbouring house built by Le Corbusier for the 1927 exhibition.

The ‘active’ element in the Aktivhaus is a mini computer, connected to the internet, that monitors weather forecasts and enables the house to respond accordingly, with different rooms heated or cooled at different times of the day. Other elements include a highly efficient heating system, web app-operated functions to control lighting and window blinds, and 17mm thick vacuum glazing whose three layers keep heat in and draughts out.

Werner Sobek believes that the Aktivhaus concept is not only applicable to new homes. “Our system is very helpful for old buildings,” he told the New York Times.

Some might feel it best to leave the imperfections as they are and not invest in major energy improvements and instead rely on the surplus energy from a ‘sister house,’ but the system can also help you decide to make modest changes to the windows or to improve the boiler.”

DEU, Stuttgart, Musterhaus Wei§enhofsiedlung, AWerner Sobek Design, Fertigstellung: 2014 , DIGITAL 100 MB 8 Bit. - ©Zooey Braun; Veroeffentlichung nur gegen Honorar, Urhebervermerk und Beleg / permission required for reproduction, mention of copyright, complimentary copy, FUER WERBENUTZUNG RUECKSPRACHE ERFORDERLICH!/ PERMISSION REQUIRED FOR ADVERTISING!

Photo reproduced with permission of Werner Sobek Design, Fertigstellung: 2014: ©Zooey Braun

Over three years, researchers will study B10’s performance as a real-life residence. The building can later be dismantled and reassembled elsewhere, and when it reaches the end of its life almost all parts of the Aktivhaus have been designed to be recycled.

With construction costs of €100,000 and the technology inside priced at a further €600,000, the Aktivhaus is hardly an affordable housing option. But eventual scaling up of production could drive those costs down.

In the meantime, the ideas coming out of the Aktivhaus project may influence those looking for ways to tackle the ongoing issues of housing shortages, climate change and fuel poverty.


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

Follow us on Twitter to see what developments in public and social policy are interesting our research team.

Further reading*

PassivHaus … a home for all seasons?

Thermal vision (energy-efficient retrofit for social housing block)

Warmer outlook (energy efficient housing)

Building sustainable homes

Footprint: three Passivhaus projects

Building the future: the economic and fiscal impacts of making homes efficient

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

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