Subjective Evaluation of Sustainability and Attractiveness Criteria of Planned Buildings: A Case Study

Abstract

Architectural competitions are regarded an important way to find close-to-optimal solutions for given building design tasks. In recent years, sustainability criteria within architectural competitions increased in importance. However, the question how to cleverly integrate sustainability criteria into the required deliverables that architects have to provide in competition entries remains widely unsolved. Even if energy calculations or tabular data are stipulated, both meaningfulness and impact on the jury decision seem to be highly doubtful. This might be due to a number of reasons: First of all, architectural competitions regularly address early design stages. In other words, large uncertainties regarding construction assemblies, glazing properties, and HVAC-systems (Heating, Ventilation, Air Conditioning) persist at this moment, thus energy evaluations come with a high level of inaccuracy. Moreover, juries that evaluate competition entries regularly consist of domain specialists for the later building usage and architects, but not necessarily encompass energy efficiency specialists. This is understandable, given the multitude of requirements within building design, where sustainability is only one out of many. Furthermore, there is no common understanding regarding clear decision criteria pertaining to sustainability. Even if certain scalar KPIs (Key Performance Indicators) are demanded, these numbers can regularly not describe the overall performance of a building design. Another important aspect is that entries to architectural competitions regularly are checked onto formal issues, but not regarding the plausibility of their content. As such, it cannot be expected that the winning and running-up projects of competitions automatically resemble the most sustainable projects. Literally, any sustainability or energy performance description has to be taken for granted, but can rarely be validated. Commonly it is argued that the winning projects of competitions are regularly the competition entries that show the most balanced mix of different attributes. This, however, is difficult to evaluate. In the present contribution we illustrate the methodology and results of a recently conducted empirical experiment. Thereby, we asked undergraduate and graduate students of architecture to subjectively evaluate a set of competition entries of a recent architectural competition for a high-density, low-energy residential housing project. The project entries were the winning project as well as the five runner-up projects. The students were provided with principle information about the competition and its principle goals and then had to rank the projects regarding different criteria. The comparison of this subjective evaluation was then compared with the competition result. Some differences between the jury’s ranking and the subjective evaluation could be observed.