This is a Passivhaus Basics blog post that gives an overview of a specific aspect of the Passivhaus Standard.

The Passivhaus Standard requires a fabric first approach and a high-performance thermal envelope. Not only does the thermal envelope need to be high performance, it also needs to have an efficient surface area in relation to the size of the building. The thermal envelope is, after all, the main area through which a Passivhaus building can lose heat.

The Heat Loss Form Factor is one way of measuring the efficiency of the surface area of the thermal envelope.

The Heat Loss Form Factor is the ratio of thermal envelope surface area to the treated floor area (TFA). This is effectively the ratio of surface area that can lose heat (the thermal envelope) to the floor area that gets heated (TFA).

In other words, the Heat Loss Form Factor is a useful measure of the compactness of a building. And the more compact a building is, the easier it is to be energy efficient. Conversely, the less compact a building is, the more insulation will be required for the building to be energy efficient.

The Heat Loss Form Factor is a measure of compactness and an indication of how much insulation will be required to achieve the Passivhaus Standard.

Passivhaus Heat Loss Form Factor

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This blog post is a review of “Hermann Kaufmann IZM: Illwerke Zentrum Montafon” published in April 2015, edited by Marko Sauer.

This is a beautiful book about a beautiful building. The IZM is a new 120m long, five-storey office building in the Montafon valley of the Vorarlberg region in Austria. It brings together, in a central location, both the civil and electrical engineers of the hydropower generation company, Illwerke Vorarlberg.

The Illwerke Zentrum Montafon (IZM) in Rodund is an unparalleled timber structure: with a usable floor area of over 10,000 m2, it was the largest office building made of wood in Central Europe on completion. Assembled in only six weeks, the timber construction above the concrete base is the first application of the LifeCycle Tower (LCT) system on the free market.

The building is an exemplar of integrated architecture. The alpine setting, materials research, modern technology, prefabrication, traditional craftsmanship, low energy / low carbon design, and social contribution all play their part in making the IZM a work of stunning Passivhaus architecture.

Hermann Kaufmann IZM: Illwerke Zentrum Montafon” is an elegantly restrained monograph of essays, beautiful photographs and clear drawings. It is, in a sense, reflective of the building itself. It maintains the very high standard of presentation and technical detail that can be found in all Detail magazines and books.

Passivhaus architecture is integrated architecture. This book details an exceptionally beautiful work of integrated architecture.

031 Exceptional Integrated Architecture

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This is a Passivhaus Basics blog post that gives an overview of a specific aspect of the Passivhaus Standard.

The Passivhaus Standard requires airtight construction. What does this mean?

Essentially it means a draught-free building envelope.

A clear airtightness strategy is required to achieve this. The airtight line needs to be continuous even when formed of different materials. And it needs to be joined up, even where there are penetrations.

Sometimes airtight construction gets confused with how a building is ventilated or with ‘breathing construction.’ This post clears up these particular confusions.

And why does the Passivhaus Standard require airtight construction?

Airtight construction is draught-free construction. It is an essential part of the Passivhaus Standard to protect the building envelope, to ensure radical energy efficiency and to provide exceptional comfort.

030 What is Airtight Construction
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A passivhaus home in almost all climates across the world will include a mechanical ventilation system with heat recovery (MVHR*). This kind of ventilation system is required for both energy efficiency and for comfort. However, to many people this is an intimidating and misunderstood aspect of passivhaus. As a result, there are various concerns and misconceptions about what a passivhaus ventilation system is and how you use it.

To address some of these issues I have enlisted the help of Zehnder, a global supplier of Passivhaus Certified ventilation systems. In this post, we explore the following aspects of a residential passivhaus ventilation system:

  1. How do I control the ventilation system?
  2. What day-to-day interaction do I need to have with the ventilation system?
  3. What is the boost function and when should I use it?
  4. When should I switch the ventilation system off?

Rupert Kazlauciunas, Senior Technical Advisor at Zehnder Group UK, very kindly provided answers to my questions

In a residential passivhaus, the ventilation system can be simple to use. It will save energy and money, while ensuring comfort and excellent indoor air quality.

029 Residential Passivhaus Ventilation System
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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.

016 What the Passivhaus Standard is Not
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