The Passivhaus Standard is the world’s foremost standard for energy efficient and comfortable buildings. Buildings certified to the Passivhaus Standard are often more energy efficient than conventional buildings by a factor of 10. In the face of climate change, architecture in the anthropocene must change. Buildings need to consume radically less energy to emit radically less CO2.
Buildings certified to the Passivhaus Standard are also incredibly successful at meeting design predictions. The performance gap is eliminated. And passivhaus buildings maintain their performance over time. The rigorous integrated design and quality assurance requirements of certification process for the Passivhaus Standard ensure this.
And yet there are many misunderstandings about what the Passivhaus Standard is. In some cases it gets confused with other aspirations. In other cases the standard gets accused of not being one thing or another, regardless of what it actually is! There is even a sense of the ‘tall poppy syndrome’ at play within the sustainable / green building community sometimes.
This blog will help clear up some of the common misconceptions around the Passivhaus Standard.
1. Not an Embodied Carbon Standard
Buildings CO2 emissions are, in simplistic terms, embodied carbon emissions or operational carbon emissions. Embodied carbon emissions are those that come from the manufacture, transport and assembly of materials and components that form a building. In some cases, emissions from maintenance, replacement, and taking a building apart or demolishing it are also included. Operational (or in-use) carbon emissions are those that come from running the building over its lifecycle.
Embodied carbon emissions can make up 20-50% of the whole life carbon emissions of a new building. It is immediately apparent that operational carbon emissions, which make up the other 50-80%, must urgently be addressed as the priority.
And this is what the Passivhaus Standard does – it radically reduces operational carbon emissions through energy efficient design. As a standard it does not require, or certify, any reduction in embodied carbon emissions. This does not at all exclude the possibility of also reducing embodied carbon emissions though. Embodied carbon emissions should be the immediate priority once operational carbon emissions have been significantly reduced.
There are more and more buildings certified to the passivhaus Standard that are also ultra-low in embodied carbon emissions. For example, this one by Architype (the company I work for) or any of these ones by Createrra are all passivhaus and very low embodied carbon.
2. Not a ‘Zero Carbon’ Standard
The concept of a ‘Zero Carbon Building’ is deeply flawed as I have written about. And the definition of a ‘Zero Carbon Building’ that might become a regulated requirement in the UK is even more problematic. Nevertheless, passivhaus could be a route to achieving the UK requirements. This doesn’t make the Passivhaus Standard a ‘Zero Carbon’ standard though.
The Passivhaus Standard is clearly defined as an energy and comfort standard. The carbon emissions from a passivhaus building will be inherently very low as the energy consumption will be very low. And the carbon emissions will be even lower if a significant portion of the primary energy consumed is from renewable energy sources. This will be true if the energy is generated on the building, on the site, nearby, or anywhere else that feeds into the energy grid.
Energy generation must shift to primarily renewable sources to be sustainable and to address climate change. However, renewable energy generation alone isn’t enough to address climate change. Radical energy efficiency is also required and this is what the Passivhaus Standard delivers for buildings.
3. Not a ‘Net Zero Energy’ Standard
This is a very similar misconception to the previous one, despite the reference to energy rather than carbon. And the majority of the reasons why ‘Net Zero’ is problematic are same regardless of whether it be focussed on energy or carbon or indeed something else.
While we definitely do need to dramatically increase renewable energy generation, defining a building by how much energy it generates is often not useful. A building needs to be comfortable and fit for healthy human inhabitation. Focussing on achieving this with the least practical amount of energy input throughout the year results in better performing building fabric. And the fabric will last the lifetime of the building, assuring reliable low energy demand and excellent indoor comfort conditions. This is what the Passivhaus Standard delivers.
On the other hand, achieving ‘Net Zero Energy’ requires balancing the energy requirements with renewable energy generation on the building. A poorly performing, uncomfortable building can still achieve ‘Net Zero Energy’ in the right location and with the right conditions. As has been commented before, even a tent could achieve ‘Net Zero Energy’!
It is however, possible for a building to be certified to the Passivhaus Standard and also achieve ‘Net Zero Energy’. And arguable, this is the most practical route to ‘Net Zero Energy’ if this is seen as a suitable and desirable target for a building. The first priority must be to radically reduce energy demand while providing comfortable healthy buildings though, and this is what the Passivhaus Standard does.
4. Not a ‘Sustainable Design Standard’
The Passivhaus Standard is a ‘Sustainable Design Standard’ with a particular focus, in a way. However, it is not a broad-ranging or holistic standard, which is what most people associate with the idea of a ‘Sustainable Design Standard’. The Passivhaus Standard does not cover embodied energy, water consumption, material toxicity, acoustic performance, proximity to an ATM or a bus route or a host of other categories that a ‘Sustainable Design Standard’ would typically include.
There is, however, a debate about which categories and items do actually belong in a ‘Sustainable Design Standard’. And a debate about the effectiveness of such standards – in terms of quality built outcomes and positive environmental, social and financial impact. The important question is: what is the purpose of a ‘Sustainable Design Standard’?
The purpose of most such standards is to nudge the industry status quo into a slightly better shape environmentally, socially and financially. The outcomes delivered by such a standard may therefore impact on many wide-ranging areas, but will naturally be relatively weak in any one area.
The Passivhaus Standard, on the other hand, has the purpose of delivering truly energy efficient, comfortable and affordable buildings. And everything about the standard is focussed on delivering just this. Therefore the standard delivers incredibly strong results in these specific areas. The Passivhaus Standard delivers radically energy efficient buildings, with no performance gap, with fantastic indoor comfort and with very low energy bills. And actually there are many other benefits than result from this deep and, what sometimes appears to be, narrow focus. No doubt a topic I will return to in another blog post.
5. Not a Points-Based Standard
The Passivhaus Standard does not have a list of items to score points against. It is a simple standard with clearly defined checks and outcomes. And all the required outcomes must be achieved. Just adding more insulation and reducing thermal bridging does not score any points. (Nor does it equate to following ‘passivhaus principles’!)
The Passivhaus Standard is an integrated standard where everything required by the standard counts. There isn’t an option to play a game of picking and choosing low hanging fruit to avoid the challenging items. There are still low hanging fruit as such but picking them (as you should) doesn’t remove the need to meet the more challenging aspects. As a result the standard delivers outcomes that are greater than the sum of the parts.
And, importantly, the Passivhaus Standard delivers what it promises. Although certifying that a building meets the standard is vital, it is not the certificate that matters in the end. The certificate is a record of quality assurance. What matters most is that buildings perform as designed. Genuine change is needed with architecture in the anthropocene, not points scoring.
6. Not a Graded Standard
There are no grades or gradations to the Passivhaus Standard. As noted in the previous section there is no point scoring, all the requirements must be met. A building either meets the Passivhaus Standard or it doesn’t. This pass / fail approach can feel unduly harsh, especially if a huge amount of effort has been put into a project, but it does bring crystal clarity and integrity to the standard. And this level of clarity drives all those involved to focus on working together to deliver a successful outcome. If a building is claimed to meet the Passivhaus Standard, exactly what this means is known, or can be checked. There isn’t a question about whether it is just a ‘Very Good Passivhaus’ or a ‘Platinum Passivhaus’, or something in between.
There is also no option to certify the design / construction / as-built stages of a project separately or individually. For a building to be certified to the Passivhaus Standard, the design, the construction and the completed building must go through the quality assurance process. So again there is absolute clarity that the completed building meets the Passivhaus Standard, it wasn’t just a good-intention at the design stage.
There are, however, different Passivhaus Standard categories or classes to be available from 2015. These include Passivhaus Plus and Passivhaus Premium, both of which include elements of on-site renewable energy generation in addition to the current requirements of the standard. Certification to the additional categories is still a matter of pass / fail though, despite the category names suggesting a graded standard.
7. Not a Prescriptive Standard
The Passivhaus Standard is a performance standard. It doesn’t dictate how a building should be designed or constructed to meet the standard.
There are certified passivhaus buildings or all different shapes, sizes and architectural styles. There are many modern minimalist passivhaus buildings, here’s one example in Portland Oregon. There are also many passivhaus buildings that are traditional in appearance, such as this Wilhelminian style passivhaus building, or these North Norfolk passivhaus Fisherman’s cottages. Location and orientation do play an important part, but aren’t rigidly dictated by the standard.
There are many Passivhaus Standard buildings constructed out of different materials also. Concrete, steel, framed timber, mass timber, insulated concrete forms (ICF) – there are examples for each material. And the same goes for cladding and finishes, it’s all possible – render, timber boards, timber shingles, metal cladding, precast concrete cladding, glass, stone, etc..
The laws of physics hold true regardless of architectural style or construction, so some design choices will carry cost or buildability consequences. And in this way the Passivhaus Standard does impose design and construction constraints. This is an opportunity for creativity to flourish, however, not a restriction on style or flair.
8. Not a Sustainable Materials Standard
The Passivhaus Standard does not dictate what materials should be used to construct a building in order to meet the standard. As noted in the previous section it is a performance standard. And the Passivhaus Standard is clearly defined as an energy and comfort standard. There is no red list of banned materials, as I have touched upon elsewhere. However, the focus and clarity of the Passivhaus Standard is where its strength comes from.
Arguably climate change is the biggest threat we face today. And our buildings offer an enormous opportunity to address climate change. CO2 emissions from buildings make up around 40% of our emissions, and we can radically reduce these emissions. The Passivhaus Standard is a reliable and trusted means of doing so through proven radical energy efficiency.
This isn’t to say we should continue using toxic materials in our buildings; we most definitely should eliminate all toxic materials from our buildings where possible. And the Passivhaus Standard is entirely complimentary with the use of healthy non-toxic materials throughout a building. However, radically reducing energy consumption and thereby CO2 emissions, is the first priority for buildings to address climate change. And therefore in some circumstances materials choices, as a lower priority, may suffer from financial or other projects constraints.
9. Not a Theoretical Standard
As mentioned earlier in section 6, the Passivhaus Standard applies to a completed building not just to the design. It eliminates the situation where good intentions fail to delivery and so there is no performance gap. And in some ways this is why it can be seen as a big challenge. How often is that level of integrity brought to the construction industry? How often do buildings actually deliver on the promises their designers make?
The Passivhaus Standard delivers not only in terms of meeting predicted energy consumption on average but also in maintaining comfort all year round, over many years. Once people live in a passivhaus building they very rarely want to leave or return to building of any other standard.
The residents of Wimbish passivhaus housing in the UK report that they:
no longer use hot water bottles and extra blankets to keep warm in winter
And it is recorded that annual gas bills are as low as £120 much to residents delight. Owners and residents in other passivhaus houses and offices report similar results. And there is all the measured data that has been collected over many studies confirming the superb performance of Passivhaus Standard buildings since the early 1990s.
The Passivhaus Standard lives up to it’s promise of delivering truly energy efficient, comfortable and affordable buildings.
10. Not a German Standard
The Passivhaus Standard did start out in Germany. However, the standard has its origins in research carried out in the USA, Scandanivia, Germany and China, among other places. It is quite an interesting history if you aren’t familiar with it. And the idea that somehow the standard only applies in a particular northern European climate can be immediately seen to be false from the historical development.
From the initial beginnings in Germany it has now spread globally as a map on Passipedia partially reproduced below illustrates. There is even a Passivhaus Standard building in Antarctica although it is not shown on this map. It is simply too good to be constrained to a single country and is now a full-blown international standard, in demand the world over.
The Passivhaus Standard is the world’s leading energy efficiency standard for comfortable affordable buildings.
11. Not Just an Energy Standard
Hopefully if you have read this far (thanks!) you will have realised that the Passivhaus Standard is as much about comfort as it is about energy efficiency. (I have written in more detail about this on another blog.) The standard does set very stringent energy consumption targets and very stringent technical performance requirements. However, the energy and technical targets are focussed very clearly on delivering exceptional indoor comfort all year round.
It is quite possible to use only as much energy as the Passivhaus Standard benchmark in a building of a much lower standard. This is only achievable in the majority of situations though by compromising indoor comfort. Either by keeping a building too hot or too cold, not ventilating the inside adequately and by putting up with drafts, cold spots, damp and mould growth. The energy bills might appear low, but the cost in health and wellbeing is high. Asthma rates, for example, in some affluent countries such as the UK and New Zealand are, quite frankly, ridiculously high. If our buildings were more comfortable and healthy this would be much less likely to be the case.
It is vitally important that as we design and construct more energy efficient buildings, indoor comfort, air quality and our health are not compromised. The key to delivering radical energy efficiency combined with comfort and health lies in both the design process and in proper quality assurance of the design and of what gets built. The Passivhaus Standard can be considered a comfort and energy efficiency standard for buildings, and it delivers healthy indoor environments.
12. Not Just a Housing Standard
It is often assumed that the Passivhaus Standard only applies to houses or housing. Actually there are single-family homes, apartment buildings, educational buildings, office buildings, high-rises, churches, swimming pools, retrofits of all kinds, and even regions, all to the Passivhaus Standard. I won’t go into it any further here, I already wrote about this in another blog post.
There are Many Things the Passivhaus Standard is Not
And this is the way it should be. Too often we try to do too many things and fail to do anything fully and completely. Standards are no exception. The Passivhaus Standard is an incredibly successful and empowering standard that is focussed on delivering what it promises: truly energy efficient, comfortable and affordable buildings. And it does deliver.
Other standard are needed too – standards for embodied energy, for water consumption and for healthy materials. These don’t need to be part of the same standard though. Simplicity, clarity and genuine results matter most of all, not how broad a ‘Sustainable Design Standard’ is.
In the face of climate change we need to radically reduce CO2 emissions. Architecture in the anthropocene must change, buildings need to consume radically less energy and emit radically less CO2. And yet energy efficient buildings must not compromise our health and wellbeing, after all, we spend the majority of our lives inside buildings.
We need more buildings built to the Passivhaus Standard. Radically energy efficient, exceptionally comfortable, healthy buildings.
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