Passivhaus
'Passivhaus' is the name of a building standard for highly sustainable homes that was developed in Germany in the early 1990s. Passivhaus is a rigorous, voluntary, design and construction standard for energy efficiency in a building. Homes meeting this standard are carefully designed and insulated so as to dramatically reduce requirements for conventional sources of warmth. Designing a home using Passivhaus principles results in ultra-low energy buildings that require little energy for space heating or cooling and thereby reducing its ecological footprint.
The 40,000 of these buildings that exist around the world, are mostly in German-speaking countries and Scandinavia. In the UK the Passivhaus Trust is an independent, non-profit organisation that provides leadership for the adoption of the Passivhaus standard and methodology. The number of Passivhaus homes in the UK has increased from just one in Wales in 2008 to more than 100 in 2012.
5 Principles[edit]
For a building to be considered a Certified Passivhaus home, it must meet a list of design and construction criteria which are laid out below. However, there are five core principles within the Passivhaus standards. To achieve the Passivhaus Standard in the UK typically involves:
- very high levels of insulation
- extremely high performance windows with insulated frames
- airtight building fabric
- 'thermal bridge free' construction
- a mechanical ventilation system with highly efficient heat recovery
The Passivhaus Trust recommends that the best way to achieve quality assurance for a Passivhaus project is through certification by a registered Passivhaus Certifier. It is reasonable to claim that a building is a non-certified Passivhaus provided that it still meets the requirements of the standard. Read more about this in our Technical briefing paper here.
What Passivhaus Isn't[edit]
As with many initiatives of this kind, there is as much misinformation as there is helpful information in the market. As Passivhaus writer Elrond Burrell says <ref> 'Passivhaus In Plain English & More - The Blog Of Elrond Burrell http://elrondburrell.com/blog/</ref> "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!" In his blog <ref> 'Passivhaus In Plain English & More - The Blog Of Elrond Burrell http://elrondburrell.com/blog/</ref> Burrell goes on to specify that Passivhaus can be defined as:
- 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.
- Not a ‘Zero Carbon’ Standard - Burrell defines the concept of a ‘Zero Carbon Building’ as deeply flawed and highlights that 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.
- 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.
- 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.
- 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.
See Also[edit]
http://www.passivhaustrust.org.uk/
Passive House Association of Ireland http://www.phai.ie/
What Passivhaus Standard Is Not
Books We Like[edit]
The Passivhaus Handbook’ by Janet Cotterell and Adam Dadeby
References[edit]
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