Foto: Frontansicht des Einfamilien-Passivhauses in Pettenbach

LEKOECOS - combined economic-ecological life cycle assessment model

The consumption of ecological and economic resources over the whole life cycle is supposed to be anticipated and optimised in the design process of buildings and refurbishments. A combined life cycle assessment model together with an economic-ecological base element catalogue considering the klima:aktiv criteria was developed based on the structure of the life cycle cost model LEKOS and the ecological valuation tool Ecosoft.

Short Description




Initial situation / motivation

Ensuring the economical and environmental sustainability of buildings requires continual optimisation throughout their entire life cycle. The sooner different planning alternatives are evaluated during the planning process of a new building or a refurbishment, the more possibilities for modification still exist, and the more greatly project decisions can be influenced.

Life cycle cost calculations are of particular interest to parties involved with construction, operation, and use, because they offer the opportunity to assess the long-term affordability of real estate already during the planning stage, whereas ecological indicators such as the global warming potential and its optimisation are especially important for environmental sustainability with regard to future environmental taxes such as a CO2 tax. So far, the corresponding analyses have been carried out separately with their respective appropriate tools.

Contents and objectives

The aim of the research project LEKOECOS is to create an easy to apply tool for determining the life cycle resource consumption of buildings. This tool will include a new building life cycle model based on the Danube University's FFG-funded life cycle cost model LEKOS and the ecological material evaluation tool ECOSOFT of the Austrian Institute for Building and Environment (IBO).

The earlier a strategic resource management is carried out in the life cycle, the more effective it is. The resulting LEKOECOS building life cycle model will therefore enable economical and environmental optimisation already during the early planning stage, a time at which basic decisions are made and many options for change are still feasible.

As a result of this task, large amounts of various data are generated, all of which need to be processed in a well-structured manner. Therefore, various measures are taken to facilitate the application of the LEKOECOS programme. These include, amongst other things, a task-related user guide and a structured, application-orientated compilation of various default values ??which may be replaced by more detailed data as they become available.

Newly developed basic elements catalogues present a fundamental measure to simplify data input. They include typical structural designs and engineering systems for office buildings, schools, and residential buildings, as well as related ecological parameters. Ready to use elements can be selected from the catalogues and adjusted as needed.

The new LEKOECOS programme will be presented to developers, planners, and facility managers and will be available for download on the project website free of charge after project completion, together with a technical description and user manual.

Methodical approach

Model development is applied as a scientific method. The new calculation model is based on the FFG-funded life cycle cost model LEKOS of the Danube University Krems and the ecological material evaluation tool ECOSOFT of the Austrian Institute for Building and Environment (IBO).

The goal is to create a calculation programme able to consistently determine a building's life cycle costs as well as its life cycle's environmental impacts (in CO2 equivalents) based on standards and applicable during the planning process. Therefore, explicit phrasing and the documentation of well-balanced and concerted assumptions and idealisations is critical for model development. The viability of the LEKOECOS programme is verified by the application of specific building examples.

Results and conclusions

Essentially, the result of the LEKOECOS project is an openly accessible and easy to use excel based tool for the joint calculation of life cycle costs and life cycle related environmental impacts of buildings. By combining economical and environmental life cycle analyses, buildings' users can at the same time optimise economical and environmental resources in coordination with a building's life cycle.

The LEKOECOS model was presented to developers, planners, and facility managers and is available for download on the project "Haus der Zukunft" website together with the project report, which includes the model documentation and a comprehensive manual.

Even though one of the greatest challenges of LEKOECOS project was to bring different methods, terminologies, and views (e.g. relating to the definition of building life cycle) on cost calculation and ecology together, similarities and synergies nevertheless still appeared. For example, model parts of the life cycle cost tool LEKOS were adjusted accordingly and used for the determination of ecological parameters; and a vice versa approach is also conceivable.

The validation of the overall model was carried out in the form of test applications based on selected buildings with the aim of checking functionality and applicability, as well as the reasonableness of individual model parts. The results of the test applications support the results of previous research projects on life cycle cost analysis of buildings, according to which building follow-up costs amount to a multiple of the construction costs already after relatively short observation periods (36 years in the test applications).

Besides, comparison of environmental impacts caused by a building's construction with those deriving from its use and operation (including demolition and removal) shows that, after an observation period of 36 years, the environmental impacts deriving from its operation also amount to well over half of a building's total life cycle's environmental impact caused by its construction.

Prospects / suggestions for future research

With the LEKOECOS model, completely new insights into the economical and ecological optimisation of buildings can be obtained throughout their entire life cycle. In future, potential economical and ecological conflicts of goals can, by this means, already be recognised during the planning phase of buildings and be solved to the best extent by optimising the planning process accordingly. Key impetus for planners' training and networking can be added with the results of project LEKOECOS.

The development of the LEKOECOS model also demonstrated the need for further research and development in the area of combined economical and environmental life cycle assessment of buildings. Research partners see a huge potential in the LEKOECOS model's consistent enhancement as well as in its application for research purposes.

Project Partners

Project management

Danube University Krems
Department for building and environment

Project and cooperation partners

Contact Address

Danube University Krems
DI Dr. Helmut Floegl
Head of the Centre for Facility Management and Security
Dr.-Karl-Dorrek-Straße 30
A-3500 Krems
Tel.: +43 (2732) 893-2657
Fax: +43 (2732) 893-4650

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