Passivhaus seems to be in the industry news every week. More and more projects are appearing all across the world.
It is often stated that the International Passivhaus Standard is the fastest growing building energy performance standard in the world. The first Passivhaus building was completed in 1991 and only 25 years later it is estimated there are now 50,000 Passivhaus buildings. This is exponential growth!
And yet Passivhaus can still be a divisive subject. There are still many excuses given for not doing Passivhaus – by architects and designers, by builders and by clients.
It is true; there are real reasons for not doing Passivhaus in some circumstances. However, in most cases the reasons are based on misunderstandings, myths and mindsets.
This post looks at 5 excuses and why they simply don’t hold water. Or rather, why they aren’t airtight!
1. Passivhaus doesn’t work in my climate!
The idea that Passivhaus doesn’t work in a particular climate is a well-worn excuse. It’s closely related to thinking that the International Passivhaus Standard is a German Standard. (It’s not.) It is true that the Passivhaus Standard originates in Germany and was first implemented in the cold climates of Germany and Northern Europe. But so does the Mercedes Benz car and it seems to work perfectly well in other climates around the world!
The Passivhaus Standard is a performance standard. A Passivhaus building must be designed using climate data for its specific location. There are different challenges for different climates, but there are very few, if any, climates where it doesn’t work.
How about an extremely cold climate? No problem, there’s a Passivhaus research station in Antarctica, it doesn’t get much more extreme than that.
Your climate might have its own challenges, but Passivhaus will work.
2. Passivhaus is too difficult to design!
Designing a Passivhaus building for the first time can indeed be daunting. There is nothing about Passivhaus design that is insurmountable for a competent architect or designer, though. It is more about having the right mindset – being willing to relearn and rethink the ‘normal’ way of designing. And once you’ve taken the red pill there is no going back, despite getting some headaches from the process!
Passivhaus does challenge some typical approaches to design. For example, getting the form and thermal envelope optimised are both important design considerations for Passivhaus. Arguably, these should be important design considerations for all architecture. Unfortunately, they are often over looked. Or in the case of building form, it is often explored in a wilful or aesthetics-only manner, ignoring the effect form has on performance.
Passivhaus demands design rigour and acceptance of additional constraints. Applying new constraints to a design process can be a challenge at first. Over time constraints that are embraced lead to increased creativity. And then the design process becomes much easier.
The Passive House Planning Package (PHPP) is a key design tool. As you design a Passivhaus building, PHPP is your best friend! You can test your ideas as they develop and compare different options – with instant feedback on the performance and whether or not it’s likely to meet the Passivhaus Standard.
The key is to start from the right place – with Passivhaus as a clear goal and with an open mind about how to achieve it. Other design aspirations don’t need to be forgotten or compromised though they might require further creativity and effort to resolve. On the other hand, shoehorning Passivhaus into an existing design (or design process) certainly is difficult. It can be just as challenging as designing a Passivhaus retrofit.
Designing Passivhaus isn’t too difficult – architects and designers around the world are embracing the challenges and expanding their creativity!
3. Passivhaus is too difficult to build!
Are Passivhaus buildings difficult to construct? It really depends on how they are designed. If they are designed with Passivhaus in mind, they won’t be too difficult to build. A well-designed Passivhaus building can be even easier to construction than a standard building due to the clarity and rigour needed in the design and documentation.
Just like designing Passivhaus, building Passivhaus requires a shift in mindset. It is about integrated design and that means it is about the construction of the building itself, particularly the building envelope, rather than bolting ‘sustainable’ features to it. It means the small details count and everyone on site needs to know that their contribution matters.
Many aspects of Passivhaus details are new to builders, such as airtight and thermal bridge free construction, and the heat recovery ventilation system. So there might be a steep learning curve at the beginning. The Passivhaus community is very supportive, though, and an incredible resource to draw upon.
Another surprise can be the attention paid to quality control. The Passivhaus certification process ensures what gets built matches what was designed and drawn. Builders used to taking shortcuts and “doing what they always do” could find this daunting. Passivhaus is a team sport though and everyone on the team is committed to the project’s success. Site teams quickly start taking more pride in their work because they know it matters and it will be checked.
Passivhaus construction is essentially high-quality construction. It might take more time and effort, or it might take a different attitude to standard construction, depending on your starting point.
In fact, it is so easy that students with virtually no construction experience are constructing Passivhaus buildings. It is fast becoming a key component of entries into the biennial Solar Decathlon competition. The younger generations recognise that we are living in the anthropocene and architecture must change. Take this Passivhaus example from Stevens Institute of Technology: the SU+RE HOUSE.
We are striving to build in a world affected by a changing climate, working to educate the next generation of innovators, and do our part to help the New Jersey Shore bounce back from the damaging effects of Hurricane Sandy. [Source]
Building Passivhaus isn’t too difficult, even students can do it!
4. Passivhaus? I prefer Net-Zero!
“Net-Zero” or some other variation on the name, is all the fashion in green building circles these days. Essentially it means matching the building’s annual energy consumption with on-site renewable energy generation. It sounds like a good thing but actually it’s problematic. In “Zero-Carbon Buildings? It’s the Wrong Target,” I discuss a whole list of reasons why it isn’t the best approach. And other people added their voices in the comments. (Although “Zero-Carbon” and “Net-Zero” is not exactly the same thing, the issues are largely the same.)
That said, if “Net-Zero” is the target, then Passivhaus First is the best approach. By radically reducing energy consumption with Passivhaus, it is significantly easier, and cheaper, to match the energy consumption with on site renewable energy generation. And a Passivhaus building with its energy needs reduced by up to 90% will make “Net-Zero” possible in many locations other approaches won’t. For example, sites with poor solar access whether through shading or simply plot size.
Whether or not some definition of “Net-Zero” is your aim, Passivhaus First is the critical approach to take. Radically energy efficient buildings immediately reduce our reliance on fossil fuels. And for renewable energy generation to produce a significant portion of our energy, this is what we need. And it’s what the world needs in the face of climate change!
In many ways, Passivhaus enables the use of renewable energy to power buildings. Passivhaus reduces the amount of energy storage needed to cover the mismatch between daytime renewable energy generation and night-time energy consumption. And it goes a long way to help with the seasonal mismatch between peak summer renewable energy generation and peak winter energy consumption.
The North American Passive House Network has published a book on this subject: “Net Zero Energy Buildings: Passive House + Renewables”. To quote Professor Dr. Wolfgang Feist, Director of the Passive House Institute, from the foreword;
In North America, the combination of energy efficiency and on-site sustainable energy generation is becoming more common, as front- running cities and regions look to set the new norm of building: cost-effective and sustainable. The step is long overdue, as over a third of the total energy consumption in industrialized countries results from building operation – and up to 90 per cent of this energy can be saved with Passive House. [Source]
“Net Zero Energy Buildings: Passive House + Renewables” was written and edited by Mary James, of Low Carbon Productions. You can read my review of one of Mary James’ previous books, “American Passive House Developments” here. NAPHN have generously made the book available as an electronic flipbook, which you can read below. (Click the left-hand icon below the flipbook to view it in fullscreen.)
If Net-Zero is your aim, start with Passivhaus.
5. Passivhaus costs too much!
This is sometimes an excuse to avoid Passivhaus. And sometimes it’s a question: does it cost more to build to the Passivhaus Standard? Unfortunately, the answer isn’t a simple yes or no. And, is costing more the same as costing too much? After all, should a high-quality, high-performance building cost the same as a building that barely meets the legal minimum standards?
If you want to build to the minimum legal standards and at the largest floor area your budget will stretch to, then yes, by comparison Passivhaus will cost more. Except, of course, where the legal standards are close to, or the same as, Passivhaus. This is already the case in many parts of Europe. In Brussels region where Passivhaus is mandated from 2016, they found that the cost of Passivhaus came down in the 5 years leading up to the mandate taking effect. Costs came down so much that sometimes it was cheaper to build Passivhaus than not to!
If you are new to Passivhaus and don’t have anyone experienced on your team, then yes, in all likelihood, Passivhaus will cost more. As with anything new, there is a learning curve. There is a simple way to overcome this, though: include an experienced Passivhaus expert in your team!
If Passivhaus is new to the market you are building in, then suitable components, such as high-performance windows and heat recovery ventilation systems, are likely to be expensive. In this case, Passivhaus will probably cost more initially. As the market grows and matures, the costs will come down. Energy efficient fridges appeared to cost more in 1997, but by 2003, there was no correlation between energy efficiency and cost. Similarly, in Vienna, once the market had matured, there appeared to be no correlation between Passivhaus and construction costs.
It also depends on the size and type of building in question. Clearly a larger commercial building has far more opportunities for design and construction efficiencies than a small single-family residence. But this applies to construction in general; it’s not specific to Passivhaus.
Despite any, or all, of these factors there are still Passivhaus buildings being delivered around the world for no additional cost.
In the UK, Architype has delivered a number of Passivhaus schools all within standard (and reducing!) school budgets. (Full disclosure: I work for Architype.) You can see some of the details in this presentation.
Sebastian Moreno-Vacca, of A2M architects, presented an update from Belgium at the UK Passivhaus Conference in 2014. In his presentation, he joked about never having any additional budget to deliver Passivhaus, otherwise their fees would have been higher based on a percentage of the construction costs! This was the case even before it was mandated in the Brussels region.
In the US, there are a number of architects and builders that are able to deliver Passivhaus with a standard budget. Take this New York Times article, for example, it reports that architect Chris Benedict is already delivering multifamily Passivhaus buildings at no extra cost:
“It wasn’t a huge leap for me personally to be doing passive house,” Ms. Benedict said, “because I’d already been looking at how to solve these energy issues in buildings, and how to do it for the same price as typical construction. So we were able to deliver these buildings without additional cost, and it was a big goal for us.” [Source]
These examples all refer to the capital build cost only. If running costs are also taken into account, Passivhaus is even more cost effective.
Your project might face specific challenges, but Passivhaus can be designed and built cost effectively.
Passivhaus, there’s really no excuse not too!
Whatever your climate, Passivhaus is possible. The more extreme your climate, the more you will benefit from Passivhaus. The milder your climate, the easier it is to achieve the International Passivhaus Standard
Passivhaus doesn’t need to be difficult to design if you take the right approach. Get the right people on your team and learn how to be creative optimising the building form.
Passivhaus isn’t hard to build. It’s about taking an integrated approach and building to a consistently high quality. Even architecture students can do it.
Passivhaus is the perfect starting point for a “Net-Zero” building. With energy demand down as much as 90%, meeting energy needs with on-site renewable energy generation is feasible and cost effective.
Passivhaus can be designed and built cost effectively for little or no budget uplift. There are plentiful examples of this from around the world. If Passivhaus is new to your region, it might take some time to reach this point, so don’t wait!
There really is no excuse; all new buildings could be Passivhaus!
The world needs Passivhaus architecture, so start today!
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