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.
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.
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.
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