Plants in office buildings may bring several advantages. These are mostly related to the thermal, aesthetic, psychological, comfort level, and sound attenuation point of view. The research project at TU Delft aimed in defining the thermal performance of the double skin facade with plants. For this reason a simulation model was developed and validated. After validating, the simulation model could analyze an influence of plants on the performance of the double skin facade. Further simulations of the total building proofed that plants can contribute to creation of comfortable indoor climate and saving energy. Finally, constructional aspects of applying plants in the double skin facade are mentioned. (C) 2004 Published by Elsevier B.V.