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Oekoindex OI3

The instrument for environmental building optimisation

Choosing the right building material is becoming increasingly important, as the amount of energy required to construct a building is about the same as it takes to heat a low-energy house for 50 years. Environmentally friendly construction takes into account the best possible thermal insulation, renewable energy sources and ecological building materials.

What is assessed?

The Oekoindex OI3 assesses the ecological quality of all materials based on the environmental indicators global warming potential, acidification potential and the need for non-renewable primary energy. The Ökoindex OI3 can be calculated for building materials, constructions and entire buildings. As a single figure, the indicator provides quantitative information on the potential for global warming, acidification of the environment and the consumption of non-renewable energy resources.

How is it assessed?

The Oekoindex OI3 calculations are based on the IBO reference value table for building materials and can be calculated using various computer programs, e.g. eco2soft. Using a balance border method (reference limits BG1 to BG6), it is possible to look at everything from the thermal building envelope (BG0) to an overall view of the building (BG6). The reference limits BG0 to BG3 are predominantly used in Austria.

From the balance border BG3 onwards, the service lives are also taken into account for the component layers. This not only takes into account the actual construction of the building, but also the required renovation and maintenance cycles of the component layers during the building's lifetime. The standardised period under review is 100 years.

Detailed information on the balance border method as well as precise calculation rules are presented in the current OI3 calculation guide. You can download this guide and other versions in PDF format from the right side of this page (only in german). Visit for general and further information.