Before you get to the technical requirements, here are

5 things to know aboutPASSIVHAUS

elrondburrell.com/blog/5-things-to-know-about-passivhaus

This is a presentation from:

PASSIVHAUS IN PLAIN ENGLISH & MOREA blog by Elrond Burrell – UK Architect & Passivhaus Designer

elrondburrell.com

The first thing you read about Passivhaus is often the set of technical requirements and performance metrics.

It’s got to be airtight. No thermal bridges are allowed. 15kWh/m2.a, 10W/m2, 120kWh/m2.a, 0.6 ach. . . But these figures don’t help you understand how to design a Passivhaus building. These figures don’t tell you what is different about designing a Passivhaus building to designing any other building.

Passivhaus might be the world’s most stringent and fastest growing building energy efficiency standard, but does it work in urban locations? Must a Passivhaus building strictly face south?

This presentation is a simple and brief introduction to 5 things to know about Passivhausbefore you get into the technical requirements:

1. Integrated Design2. Location3. Orientation4. Form5. Construction System

Once you have a grasp of these 5 things, then you’ll be in a good place to start digging deeper into what is required for Passivhaus.

Including some key features and ticking the right boxes will not get you a building that meets the international Passivhaus Standard.

Passivhaus is fundamentally about design. And it is best approached as an integrated design process with the whole design team involved.

Passivhaus is a fabric-first standard where the building delivers very high performance, by design, for the lifetime of the building. It relies on building physics and carefully integrated, minimal building services and technology.

It eliminates the need to bolt expensive additional technology onto a poorly performing building. And it eliminates the risk of bolt-on green-bling compromising the architecture.

Passivhaus is possible and suitable anywhere in the world. Rural, suburban and urban locations are all possible. Verified location-specific climate data must be used in the design process.

Passivhaus initially started in Germany and then spread in northern Europe. Now there are certified Passivhaus buildings all over Europe and Scandinavia as well as in the US, Canada, Mexico, Indonesia, New Zealand, Australia, Japan, China, South Korea and other places.

However, Passivhaus is a performance standard. An urban Passivhausbuilding in Jakarta will not be designed and constructed the same way as a suburban one in Darmstadt. You can be sure that they will both achieve the same level of indoor comfort and energy efficiency, though.

The international Passivhaus Standard is not the same as “Passive Solar Design." It does not require buildings to strictly face south or to include significant thermal mass. Passivhaus picks up where the "super insulation" movement of the 1970s left off.

However, solar heat gain is still an important factor in reducing energy consumption and orientation remains important. Solar heat gain is calculated accurately within the Passivhaus Planning Package as part of the design process. In Passivhaus, solar heat gain is optimised not maximised.

Smaller buildings with fewer occupants (for example, a single family house) tend to benefit more from good solar heat gain (but watch out for overheating!) Larger buildings with more occupants and electronic equipment (for example, an office or teaching facility) have more internal heat gains and are, therefore, less dependent on solar heat gain.

Passivhaus does not dictate a particular building shape or form.However, the laws of physics are clear: a more complex form with increased surface area will lose more heat than a simple form with less surface area.

Physics is also clear: the more external surface area a building has relative to the usable floor area, the more energy will be needed to heat, cool and ventilate the internal space.

Buildings with complex forms can achieve the international Passivhaus Standard, however, more insulation and costly details will be needed. Buildings with simple forms are more effective in terms of building physics and therefore more cost-effective to achieve Passivhaus.

This is true for any building, the laws of physics apply, regardless!

Passivhaus does not require a specific construction system or material. It works with almost all construction systems - timber, steel, concrete, straw, hybrids, you name it.

Passivhaus is a fabric-first approach. It focusses specifically on ensuring that the building fabric performs to the highest standard of airtightness and thermal insulation. This allows building services to be simplified and minimised - the fabric does all the heavy lifting of keeping the building warm and cool.

Whatever construction system is used, it must be able to achieve an airtight and thermal-bridge free building envelope.

There is no need to choose a novel build system for a Passivhaus unless other factors are driving the decision or you want the additional challenge.

Photo: Passive House Instituteelrondburrell.com/blog/5-things-to-know-about-passivhaus

Passivhaus is fundamentally about design.Passivhaus is the world’s most stringent and fastest growing building energy efficiency standard because it is about design. (And because it delivers what it promises.)

Start with getting the Passivhaus design fundamentals right. Then use the PHPP as one of your design tools and work with the Passivhaus performance metrics as design constraints.

Don’t let the performance metrics of Passivhaus put you off, understand the design approaches and get started.

Ready to dig deeper?

1. Integrated Design – Passivhaus: Simple but not easy2. Location – What the Passivhaus Standard is Not3. Orientation – Passivhaus: Solar Orientation Doesn’t Matter. Or Does It?4. Form – What is the Heat Loss Form Factor?5. Construction Systems – Passivhaus Construction: Not Just Timber

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