Nowadays everyone claims to design sustainable buildings and offer green design solutions. But what does it actually mean?  Is a so-called sustainable home automatically environmentally friendly?  How do you distinguish between real sustainable design and one that claims to be?

The following article is an introduction to a step-by-step series that brings together all the elements that make up the sustainable design into one simple overview.


The word first appeared in the Brundland Report (1987). Sustainability is defined as “a concept which deals with mankind’s impact, through development, on the environment. Sustainable Development is “development which meets the needs of the present without compromising the ability of future generations to meet their own needs.” Today’s environmental problems, like air pollution, are largely a consequence of the unsustainable consumption of natural resources and the mismanagement of waste products. Sustainability is about environmental protection, sustained economic growth and social equity”.

Sustainability and Gruen Eco Design

We at Gruen Eco Design are passionate about sustainable design and committed to finding the best solutions for our clients and the environment. We believe sustainable design can and must be affordable and as a matter of course should be integrated naturally throughout the whole design process, rather than designing something and trying to make it sustainable later.  My name is Simone Schenkel and I’m the certified passive house designer at Gruen Eco Design. Thanks to my architectural studies in Germany, an essential part of my education was based on sustainability as well as passive house design. Due to its strict regulations and building requirements, Germany was able to achieve its Kyoto targets three years early and is currently the “world’s leader in climate protection”. I trust that as Australians we will adopt stricter requirements, as we all play our part in saving energy and protecting our environment. In the meantime, I see it as my mission to talk about sustainability and how to save energy passively as well as actively.

The basics of sustainable design

Passive Solar Design aims to maintain interior thermal comfort and to reduce the need for mechanical heating or cooling by allowing the structure of the home itself to collect, store and redistribute heat.

Please note, there is big difference between Passive Solar Design and Passive House Design. We are just talking here about passive SOLAR Design. For more info about Passive House Design and why we believe once you know more about it and understand it all there is no way back, please read our other articles about passive house design. But regardless, even when designing and building a passive house, the principles here are still important and if following them make it easier to build a passive house as well.

It’s important to note that all sites are different and that there will never be a final or the best design solution. However, there are common features and approaches that need to be applied to every job and it doesn’t matter if you build a townhouse in Melbourne or an apartment block in Alaska. Things like:

  • Optimal House Siting
  • Good Solar Access
  • Thermal Comfort
  • Adequate Insulation
  • Good Windows
  • Thermal Mass
  • Minimising Thermal Bridges + Air Leakage
  • Specifying Sustainable Materials

Each of the above points is important for the energy efficiency of a building. Yet they all need to work together if one of the elements is misapplied it can jeopardize the performance of a building.

Here is a brief description of the most important things you have to consider when thinking about sustainable architecture.

House Siting  and Solar Access

The siting and orientation of a building are essential to achieve good solar access and hence good energy efficiency. The house needs to be designed according to the site and must respond to specific site conditions to maximize free solar energy. Moreover, it’s important how the rooms are arranged; the right zoning can significantly help save energy otherwise needed for heating and cooling.

More details about how to locate a house on the site and solar access are coming soon.

Thermal Comfort

Why are some houses always uncomfortable and freezing even when the heater is on? Human thermal comfort describes the state of mind that expresses satisfaction with the surrounding environment and refers to several conditions in which the majority of people feel comfortable. Thermal comfort is affected by a range of factors such as convection, conduction, radiation and evaporative heat loss, so even if a heater is on, cold air coming from the window will leave an uncomfortable sensation.

More details about thermal comfort and why it is so important are coming soon.


Adequate Insulation

Thermal insulation is a fundamental factor to achieve thermal comfort for occupants. Insulation reduces undesirable heat loss or gain and can lower the energy demand for heating and cooling systems. The ability of insulation is evaluated by its R-value. Nevertheless, an R-value does not consider the quality of the construction, the application of the insulation or local environmental factors for a building. The building codes specify requirements for every climate zone but keep in mind these are bare minimums only and not best practice.

More details about insulation and which insulation you should choose for your project are coming soon.

Good Windows

Is double glazing worth its money? The answer is YES, but ONLY if it is installed correctly without a cold bridge (thermal bridge). A window or a door is essentially a hole in the wall and responsible for most of the unwanted heat loss or gain.

More details about windows and what makes windows energy efficient is coming soon.

Thermal Mass

Thermal mass is the capacity of an object to store heat. It is an effective way to improve thermal comfort in a building since it will absorb heat when the surroundings are hotter than the mass, and give heat back when the surroundings are cooler. When situated well and in combination with passive solar design, thermal mass can play an essential role in saving energy and be used actively for heating and cooling.

More details about thermal mass and how you should install it are coming soon.

Minimising Thermal Bridges and Air Leakage

Ventilation is the process of “changing” or replacing air to regulate temperature and moisture control amongst other things. By applying the right design features, natural ventilation and cross ventilation can be used to control indoor temperature and therefore reduce the energy bill significantly. For these reasons, controlling the air movement is essential. Thermal bridges and air leakages will increase the need for supplementary mechanical cooling and heating.

More on how to avoid thermal bridges and air leakage is coming soon.

Specifying Sustainable Materials

What makes a material environmentally friendly and what makes it green? Choosing materials for a building requires careful consideration of products and materials that have a reduced impact not just on the environment but also on the health of the occupants.  Origin, manufacturing process and the life cycle of a product are just some of the properties that play a decisive role in the selection of materials.

For more detailed information about each pillar please have a read through our further articles.