How Environmentally Sustainable Is a Passive House?

The world view has changed over the last couple of decades with increased recognition being given to the environment and the end result of our actions. In particular, the main theme that seems to come through is that we cannot continue using natural resources at the rate we are currently doing without having to deal with the environmental consequences.

Herein comes forward the concept of sustainability and the principles it entails. Even the definition of the term has been the subject of much debate. At last count, around 500 definitions have been brought to the forefront of discussion. However, the most widely used is the one from the Brundtland Report: “Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs”.

You might think what does this have to do with the building industry? When you consider the fact that this sector has been one of the slowest to react to this shift in the global mindset, the answer in its simplest form is, actually quite a lot. This has mostly to do with the greenhouse gas (GHG) emissions and the sheer variety of ways buildings can have an impact:

Through their design
Location orientation
Their relationship with their surrounding landscape
The materials used in construction
Their design elements used in their interiors and exteriors
The behavioural pattern of their occupants with regards to their electricity and water usage

Taking into account all of the above, we thought it would be beneficial to write an article about how sustainability can be achieved in the building industry and how the Passive House approach can be the solution.

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Sustainability in Construction and Architectural Design

At its core, sustainable construction considers the materials, site, energy, and water as its main resources. The five basic principles of sustainable construction are:

Focus on a reduction in the consumption of resources
Achieve maximum reuse out of your resources
Consider recycling materials at the end of the life cycle of a building
Due consideration must be given to the natural systems around a building site
Toxic materials and by-products need to be eliminated in all the life cycle phases

When it comes to the building industry, construction is just one side of the coin. You cannot discuss sustainability in this sector without discussing how this can be achieved in architectural design as well. The existing research on the topic has come up with the following principles a green building design needs to stick to:

It needs to take into consideration resources and energy efficiency
An ecological and socially sensitive use of the land needs to be employed
It needs to actively reduce the adverse human impact on the natural environment
Aim to improve the quality of life and economic well being

We can easily say that just by looking at the definition of Passive House you can immediately see how it encapsulates the vision of sustainability both in construction and architectural design. However, we do not like to leave things unexplained. Therefore, we will show exactly how the Passive House standard addresses the thorny issue of sustainability in the following categories:

Energy efficiency
Heating
Ventilation
Durability
CO2 emissions
Adaptability to the needs of the surrounding environment

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Passive House and Energy Efficiency

Due to its rigorous principles, a Passive House is specifically designed with energy efficiency at its core. For example, it has been proven that a Passive House requires as little as 10% of the energy used by conventional buildings.

If we take a look at the first Passive House ever built, which is in Darmstadt, numerous measurements taken have shown that even when daily temperatures fell below -14°C, the temperature inside the house remained at or above a comfortable 20°C. And all this has been achieved without the use of a conventional heating system.

The heating demand of the ‘original’ Passive House was shown to be so low that just two 75W light bulbs were deemed to be sufficient to heat up a 20m² room. If we put this in today’s perspective of the planets’ dwindling non-renewable energy resources, these results cannot be overlooked.

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Passive House Tackles the Issues of Heating and Ventilation

When it comes to heating, the Passive House standard excels at utilising with extreme efficiency what is known as ‘waste’ heating. This refers to the energy normally ignored by conventional buildings: the heat generated by electrical appliances and that of the occupants.
Through the use of superior insulation and controlled ventilation, a Passive House can contain part of this ‘waste’ heat inside of the house and use it to keep the interior temperature at a comfortable level.

In the previous paragraph, we briefly broached the subject of controlled ventilation. But what exactly does this mean? Essentially, a Passive House uses what is called a heat recovery ventilator to replace stale with fresh air. In the process of doing so, the incoming air is warmed by using the heat from its outgoing counterpart.

This sophisticated ventilation system basically ensures that the Passive House ticks at least two principles from the sustainable construction and architectural design handbook:

Actively reduce the adverse human impact on the natural environment
Achieve maximum reuse out of resources

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The Passive House Approach to CO2 Emissions, Durability, and Adaptability

Durability

Simply put, Passive House buildings are designed and built to last. Due to their envelope first approach and their airtight planning and execution, buildings built to the Passive House standard are unaffected by moisture damage and the build-up of mould caused by it.

Let us go back to the very first Passive House constructed in 1991. It has shown that, by adhering to the transparent and easy-to-check quality assurance procedures employed by the Passive House standard, it was still performing as planned all these years later. Thus proving that from the very beginning Passive Houses have made durability one of their strongest characteristics.

CO2 emissions

As mentioned previously, Passive House is a performance-based, envelope first building standard with a proven track record in reducing the heating and cooling demands of buildings by up to 90%.

This not only means that it drastically cuts the operative emissions of buildings but due to the way it was thought out, the Passive House approach also supports the uptake of renewable energy. This makes Diana Ürge-Vorsatz’ (a member of the Intergovernmental Panel on Climate Change) statement all the more accurate: “Passive House is one of the rare solutions where you can have your cake and eat it too”.

Adaptability

What are the principles of a Passive House? Put simply they are:

Airtightness
The use of high-quality windows
Climate applicable insulation
Avoidance of thermal bridges
Account for sufficient ventilation

These principles, which are rooted in building physics, give the Passive House standard international applicability, perfect for new build or retrofitting projects. The type of buildings that can make use of the Passive House mindset are so diverse it can include indoor swimming pools, schools, hospitals, or even factories.

Because Passive House is not an architectural design but simply a quality standard, it makes it amenable to any kind of architectural style or locally sourced building materials. Put simply, Passive House can adapt to the needs of a project, no matter the climate or local environment.

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Passive House – Sustainability Achieved?

The best way to answer this question is by simply looking at how many principles from the sustainability handbook the Passive House approach actually meets:

Focus on a reduction in the consumption of resources
Achieve maximum reuse out of resources
Recycling materials at the end of the life cycle of a building
Due consideration must be given to the natural systems around a building site
Toxic materials and by-products need to be eliminated in all the life cycle phases
It needs to take into consideration resources and energy efficiency
An ecological and socially sensitive use of the land needs to be employed
Actively reduce the adverse human impact on the natural environment
Aim to improve the quality of life and economic well being

A keen eye will notice that the above list includes all of the criterias a building needs to meet in order to be called sustainable. Passive House building is the best standard we have currently in the world, to meet the sustainability criteria. We should take the Passive House standard as the baseline and build up from here. There is still much from the sustainability handbook that can be addressed further by the building industry.

What is even more important to know is that the Passive House standard has gained massive traction in Australia through its introduction in the Green Star Rating by the Green Building Council Australia and highly suitable for ‘The Living Building Challenge’.

When you add into the mix that the European Union is actively pushing for all member states to have nearly Zero Energy Building, it is no wonder that the Passive House standard is leading the way in the sustainability race.

If this article has piqued your interest and would like to learn more about the basics of a Passive House, click here for further information.

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