Passivhaus overheating shouldn’t happen: it’s one of the criteria of the international Passivhaus standard.
Even so, people sometimes ignore this requirement during the early stages of the design process.
It shouldn’t be ignored. Overheating is a key design issue and should be addressed from the beginning as an integral part of the Passivhaus design process.
But how?
This blog post is a simple guide to preventing Passivhaus overheating by design.
Architecture is often described as the combination of art and science. The role of art in architecture is understandably subjective and open to debate. However, what about the role of science in architecture?
Clearly buildings do obey the laws of science, as they must. And specifically, the structure and services of a building are calculated and designed using physics. Understandably, it is most often these areas of science that get expressed in architecture. We can see this, for example, in the structural expressionism of Santiago Calatrava or in the romanticised high-tech style of Richard Rogers.
Aside from structure and building services, however, does science inform architecture in any other ways? Perhaps not as often as it should! As I wrote about previously, design is central to passivhaus. And science is central to passivhaus design – at the macro level of form and orientation, and at the micro level of airtightness and thermal bridging.
Science is a reason to Love Passivhaus!
Architectural design is typically carried out with little or no environmental consideration integral to the process. Once the design has reached a certain stage environmental considerations – whether material toxicity, water conservation, carbon emissions or energy conservation or something else – are then assessed. At this point decisions are made to revise and iterate the design for better environmental outcomes or to add ‘environmental features’. We know the results of this disjointed design process and we know this has to change if buildings are going to be better for people and the planet!
Unfortunately many environmental standards reinforce this process in two ways. Firstly by being separate from the design process, often as an assessment procedure. Secondly by requiring ‘environmental features’ be added in order to score points or increase the rating of the design.
The Passivhaus Standard is different. Unlike most environmental standards for architecture, design is central to the Passivhaus Standard. And the Passivhaus Standard is central to the design process.
Design is a reason to Love Passivhaus!
This blog post is a review of “PHPP Illustrated: A Designer’s Companion to the Passive House Planning Package” published in October 2014. Sarah Lewis, architect and Certified European Passivhaus Designer wrote this delightful and chunky volume.
The Passive House Planning Package (PHPP) can seem like a monster spreadsheet at 30+ worksheets (tabs). And the last thing most architects would consider a ‘design tool’. However, once architects understand passivhaus and start to design passivhaus buildings, they quickly realise that the passivhaus spreadsheet PHPP is an essential element of the design process. For without the PHPP there would be no passivhaus buildings as Dr Wolfgang Feist writes in the foreword:
Behind the success of the [Passivhaus] Standard lies the Passive House Planning Package (PHPP), the Passive House energy balance and design tool. A tool of proven accuracy and demonstrated reliability in predicting building energy consumption…
The next step up is to gain enough understanding and fluency with the PHPP to fully integrate it as a passivhaus design tool. And that is where the strength of this book lies for passivhaus architects.
Sarah guides the reader towards fluency with the passivhaus spreadsheet PHPP using three key tools throughout the book:
Camden Passivhaus, the first certified passivhaus building in London UK, is used throughout the book to give real-world context each step of the way. It is also a seminal bere:architects passivhaus project and one that Sarah worked on previously while as a Director of the practice.
An unfamiliar tool can appear as an obstacle to design. Once understood and put into practice it can powerfully inform and support design decision making.
As the EU moves towards ‘Near Zero Energy Buildings‘ and the UK moves towards implementing this by requiring ‘Zero Carbon Buildings’, understanding the Passivhaus Standard as one reliable route towards delivering ‘Zero Carbon Buildings’ is vital.
Passivhaus is known as the world’s leading building energy efficiency standard. It is also a comfort standard with stringent indoor thermal comfort and ventilation requirements. The majority of industry discussion around passivhaus focuses on the technical details and energy benchmarks required to meet the standard. While this is understandable as we come to grips with the challenges of delivering buildings to such a high standard, there is less attention paid to the benefits delivered by the standard and wider aspects of the passivhaus design process.
