The UK Passivhaus Conference took place in Leeds last month, bringing together those passionate and curious about a building design approach that achieves very low or zero carbon emissions for the occupied building.
Since the Passivhaus Institute was established in Germany in 1996, an estimated 65,000 buildings have been designed, constructed and tested to rigorous Passivhaus standards and yet, the UK accounts for only a small proportion of that figure. Germany, where the standard was established, Austria and the Scandinavian countries are still taking the lead in adopting Passivhaus principles and benefiting from the comfort and energy efficiency this design approach delivers.
While an obvious reason for this may appear to be climate, with the countries where Passivhaus is most prevalent experiencing harsher winters that we generally expect in the UK, the causes for the UK’s reluctance to embrace Passivhaus are more complex.
Firstly, ours is often a conservative design and construction market. We are, quite rightly, concerned with architectural context for residential, commercial and public buildings but this is often more of a perceived conflict with traditional aesthetics than a real hurdle to positive change. In the residential sector, there is also a perception that house buyers are looking for traditional bricks homes with pitched roofs and central heating: in essence, a move towards Passivhaus demands a break from the norm from those who design construct and occupy our buildings.
However, there is evidence that change is coming. NBT has recently supplied Pavatex woodfibre insulation and airtightness membranes to the UK’s highest airtightness scoring Passivhaus project and there are now a number of certified Passivhaus schools. Meanwhile, in the mainstream residential market, many buyers have shown themselves willing to exchange the traditional semi with gardens front and back for an apartment, and the more progressive housebuilders are experimenting with new designs and materials, such as the Taylor Wimpey CLT (cross-laminated timber) prototype homes in Oxfordshire that NBT has supplied with Pavatex.
According to the UK Passivhaus Conference, an estimated 43 per cent of carbon emissions in the UK are produced by occupied buildings, which, along with rising energy costs, energy supply uncertainty and concerns about the escalation and effects of climate change, creates a compelling reason to design and specify buildings differently. Renewable energy and low energy M&E specification can only ever provide part of the answer; the most sustainable response is to construct buildings that are so airtight and thermally efficient they need barely any energy at all for heating or cooling.
Of course, expense can be a sticking point, especially when the cost of a building is calculated in terms of the build cost alone, without considering the whole life savings to be made during the occupational phase. However, if we are serious about meeting targets for reducing carbon emissions, committed to using less energy and keen to enhance building comfort all year round, Passivhaus or near Passivhaus standards must start becoming a significant part of the mainstream.