Costs and benefits of daylight redirection systems: integrated assessment of daylight redirection systems and daylight-dependent control systems to reinforce daylight utilisation in existing buildings.

Content Description





Daylight redirection systems do not only contribute to improve physical and mental well-being in rooms, they also help to save energy in the lighting sector. Substantial energy savings can be achieved, particularly, in optimised combination with efficient artificial lighting systems. What is missing presently, are well prepared information for builders, owners, and caretakers on the different possibilities as well as well-founded selection criteria on suitable daylight/artificial lighting combinations. The project Lichtblicke, "bright spots", intends to fill this need.


The project consists of the following head modules:

  • Data and experience are researched, clearly prepared, and made accessible in a database.
  • Based on the gathered information, a rating system will be developed to assess life cycle costs and benefits of individual systems as well as of system combinations.
  • In addition, individual systems are to be installed for view in model rooms in collaboration with the training course Erneuerbare Energie, "renewable energy", of TGM Wexstraße Vienna , (

Intended Objectives

At project end, a tool (consisting of database and rating system) will be available offering builders, owners, and caretakers information on costs and benefits of daylight redirection systems. The tool will contribute to support the distribution of these systems and open new marketing possibilities to the manufacturers. The objective is to reinforce and optimise daylight utilisation, primarily in schools and office buildings.

Method of Preparation and Used Data

The model philosophy for the rating system is oriented on the principles of integrated resource planning - an instrument used for the first time in the electricity industry, focusing on the service instead of the product and combining measures on cost reduction both on supply and demand sides.

For cost calculation of different technological options including all business parameters, we specifically rely on the methodics of Swoboda 1996 , for calculation of the long-term economic system costs. For the estimation of external costs and benefits, certain effects such as air pollutant emissions, greenhouse gas emissions, etc. are quantified by means of GEMIS-Austria and, subsequently, monetarised based on external costs, as accounted for in the literature . GEMIS-Austria is a computer model for the calculation of environmental effects of energy systems that observes the entire life cycle of the energy system and, thus, all environmental effects.

Data underlying the estimation model and information contained in the database are determined by literature- and internet-research as well as by guideline-supported interviews with manufacturers and users. Practical usefulness of the results is guaranteed by co-operation with lighting planners who command long-term experience in the area of daylight utilisation.

Project Partners

Project manager:

Heidelinde Adensam
Österreichisches Ökologie-Institut für angewandte Umweltforschung

Project partner:

Bartenbach LichtLabor GmbH
Bundesimmobiliengesellschaft M.B.H.
ÖISS - Österreichisches Institut für Schul- und Sportstättenbau
TB Dr. Alexander Bakos
Kolleg Erneuerbare Energie


Heidelinde Adensam
Österreichisches Ökologie-Institut für angewandte Umweltforschung
1070 Wien, Seidengasse 13
Tel.: 01/523 61 05
Fax : 01/523 58 43