For the second instalment of our series on sustainability, Director and Head of Sustainability Simon Bell explores the lesser-known benefits to Passivhaus design, which positively impact both humanity and the natural environment.
“We must recognize this emergency and respond with meaningful change in how we develop our towns and cities – and in doing so, living more lightly within the natural world.”
In a month where we are witnessing the devastating impact of climate change and hearing the warnings from the IPCC, we cannot continue with business as usual. As individuals, built environment professionals, clients and policy makers we must recognize this emergency and respond with meaningful change in how we develop our towns and cities – and in doing so, living more lightly within the natural world.
We have the tools to do this already. The Passivhaus Standard is one part of our sustainability toolkit. It isn’t risky, it isn’t particularly innovative, it is in fact a proven standard, having been around for 30 years, and is built on sound building physics. It is an air quality, comfort, energy efficiency and construction quality standard. While it is often known for its ultra-low energy use targets, those metrics are really the by-product of designing an efficient building which provides excellent indoor air quality and thermal comfort for its occupants. Much of the standard is simply the result of good design; orientation, efficiency of form, efficiency of space, excellent fabric performance, ventilation that works, robust detailing and consideration of the real-world occupancy and use of the space. The Passivhaus Standard can be applied to both new builds, and perhaps more importantly in retrofit, enabling our existing building stock to be radically improved. Crucially, Passivhaus is based on robust performance modelling of each building, ensuring that the designed targets are achieved in the real world. Remember the Volkswagen emissions scandal? Buildings designed and certified to Building Regulations today generally perform much worse than they will on paper leading to the infamous ‘performance gap’. In any other sector of our economy – cars a prime example – we wouldn’t think twice about adopting an established standard with a proven record of delivering what it says on the tin, yet in construction we continue to build inefficient buildings which impact people, society and the environment. This has to stop.
But how does the Passivhaus Standard help us to live more lightly? There is clearly the energy use metric, so whether it’s a new build or retrofit, we know our energy requirement for the building will be significantly lower than what we have built before. This enables us to heat these buildings efficiently using heat pump technology and offers the opportunity to generate all or part of the power demand through on-site solar panels, effectively eliminating the requirement to burn fossil fuels. It also reduces the demand on the national power grid, which is particularly important as we drive to use decarbonised electricity to heat our homes and power our vehicles. Anything we can do to reduce energy use at source will offer wider environmental benefits by reducing the need for finance and resources given to developing our power infrastructure.
The Passivhaus Standard when rolled out at scale can also offer multiple societal benefits, supporting our nations to live more lightly. The improved wellbeing outcomes from living in healthy, well ventilated and mould free homes, with good natural daylight and appropriate sound insulation reduces days lost to illness – both physical and psychological – and the consequential burden on our health and social services. The improved educational attainment from learning in comfortable, well-ventilated schools helps improve attainment and ultimately leads to improved opportunity for individuals and communities. More importantly, building social and affordable homes to the Passivhaus Standard can lift families out of fuel poverty, removing the difficult choices they may make about putting food on the table or heating their homes.
What about the impact of the materials we use in Passivhaus Buildings? To date, the Passivhaus Standard has been largely material agnostic, and has not required the specific use of natural materials. There is currently no embodied energy or carbon target within the Standard, although this is something which is being considered and, in my view, should be included as an integral target. As I said though, the Passivhaus Standard is only one part of the sustainability toolkit and we must bring that together with other tools to design buildings which offer the best sustainability outcomes. In all projects we must consider the need, location, client and indeed the local community and supply chains, so that we can make the best material decisions – whether that be refurbishing existing buildings, using locally sourced materials, recycling pre-existing man-made materials, or using natural materials for construction.
While the Passivhaus Standard can certainly help us to live more sustainably, is that enough? To live sustainably implies living in balance with nature. Given our impact on the natural world and lack of meaningful action to live sustainably over the last 40 years, we are now faced with a situation where living in balance is no longer enough. We now must consider how we can repair our world through restorative and regenerative design, looking at every project and ensuring our designs work in harmony with natural systems. While the Passivhaus Standard does not necessarily award extra points or set targets for this, there is certainly nothing in the standard which prevents these approaches. The new classifications of Plus and Premium do support energy generation and export, and as already noted we hope that embodied carbon targets encouraging the use of natural and recycled materials will be implemented in the Standard in the near future.
The Passivhaus Standard is the best tool we have to hugely improve the quality and efficiency of both our new and existing buildings stock to support a sustainable and restorative future. Every day we don’t deploy it at scale is adding to the burden and cost we pass on to our future generations. Rather than place our hope in some future innovative technology to solve our climate crisis we need to act now with the tools we have.