This book is aimed at a broad readership, including builders, self-builders, architects, energy assessors, registered social landlords (RSLs), planners, building control officers, politicians, clients – in fact anyone who is, wants to be or should be involved in future housing provision.
It is intended to provide knowledge of both the methodology and the skills needed to achieve genuinely low-energy buildings, whether new or retrofitted, that perform as intended.1 In the UK especially we have a very poor record when it comes to transferring design intent into real-world building performance. Building sustainably involves a wide variety of considerations, from water use to recycling to low-embodied-energy materials, and so forth. Passivhaus focuses on the energy consumed in the lifetime of a building. This is where we make (by far) the largest carbon savings – a necessary step if we seriously want to move towards a low-carbon economy and address a less energy-rich future. This is also where we have failed to find success to date in our houses and ecobuildings. We can install solar panels on our roofs, we can reduce water use, we can recycle, we can choose to use materials with lower embodied energy. But can we radically reduce our space-heating needs?
Effectively reducing the energy consumed for space heating (or, in hotter climates, cooling) requires training and up-skilling, both of which pose significant challenges. In the UK, we are in the process of adopting a broad-based sustainability assessment system, the Code for Sustainable Homes (CSH), where points are awarded for a range of possible sustainable features – you collect the points and rise up the levels (from Levels 3 to 6, where Levels 5 and 6 are currently termed ‘zero carbon’). While the broad approach has much merit, an unintended side effect can be that fabric performance (the energy demands of the building itself) is perceived as one option among many – and other criteria are often easier, quicker and less challenging (and more exciting!) to meet. Energy in use, however, lies at the very heart of a truly sustainable architecture. If you get this right it also brings many associated benefits – health (indoor air quality), material preservation (avoiding moisture damage) and indoor comfort (consistent temperatures with no draughts). By focusing on fabric performance, Passivhaus addresses the fundamentals and ensures that these key benefits are realised.
Passivhaus may have been seen as a niche approach and as an interest for a small minority of enthusiasts, but its influence is growing rapidly. Passivhaus simply applies the laws of physics to building for low-energy use and human comfort. These are the principles we all need to understand if we are to construct buildings intelligently. Passivhaus is ‘low-energy design’ and therefore its principles should be an integral part of any sustainability assessment system, even if the targets lie a little outside the Passivhaus-certified standards, as they do in the CSH. The new Fabric Energy Efficiency Standards (FEES) being considered for inclusion in the 2013 Building Regulations, and already adopted into the CSH, bear the mark of Passivhaus influence. The application of Passivhaus principles to less demanding energy targets, and the relationship to zero carbon, are discussed in Chapter 5.
Architecture has tended to be driven by aesthetics rather than by energy performance. The fact that it has not been uncommon to believe in a future of ‘free energy’ has meant that our buildings have been relatively ‘energy-unconscious’. Once your world view turns towards considering an energy-poorer future, then Passivhaus becomes an essential contribution to addressing this problem, and it challenges us to engage with the building physics and to understand how it all works. Those with an innate fear of science need not despair – once we are prepared to have a closer look, we can grasp the principles, and we should be inspired to build our houses with greater quality and attention to detail; something we have failed to do in the past. We have tended to be rather addicted to immediate short-term solutions; Passivhaus, on the other hand, plans for the longer term – an investment now returns benefits over many decades. Quality ensures longevity.
Passivhaus is not a particular style of architecture – as can be seen from the variety of images in this book. Of course low-energy principles will inform the design, as will many other constraints, such as site location and budget! This is generally the architect’s domain, and there is no reason why aesthetic solutions should not arise as readily as in any other circumstances. Certainly design is a skill; truly beautiful and functional buildings are a lifetime challenge. Poor design is a function of our lack of imagination and not a fault arising from restrictions such as low-energy requirements. Restrictions are often what lead us towards elegant solutions.
We hope that self-builders, planners and building control officers, as well as those responsible for formulating and implementing housing policy, will all find this book useful. If low-energy building is to become the norm, the route to achieving this needs more than new legislation. There are important cultural and process issues to be considered, as well as a desperate need for good training and support. In the UK, the government is extremely reluctant to intervene in new markets. But without some supporting and enabling mechanisms, the necessary transition to a low-carbon economy will most likely be slower, and opportunities – both economic and environmental – will be lost.
New Passivhaus houses are being built at competitive rates, and these costs will further improve as the market for low-energy products grows. Our future housing requirements need to be met with economically viable solutions – and Passivhaus, with its focus on fabric efficiency, offers just that.