A computer system for enabling designers and entrepreneurs a simple, convenient and quick manner to select different building technologies for the building's envelope is presented. The selection is achieved by examining the profitability of each alternative, while presenting its performance ability on the basis of a large number of criteria. This paper looks at the application of multiple criteria decision making (MCDM) techniques in the assessment of environmentally sensitive construction methods. Cost benefit analysis is one of the conventional techniques used widely by public and private sectors in the appraisal of projects by means of a market approach. However, externalities, intangibles and environmental impacts need to be incorporated into the evaluation and a strategy needs to be developed to give these factors proper consideration. Due to the fact those impacts can hardly be assessed in economic terms within a market approach framework, MCDM techniques, like Compromise Programming (CP), are investigated and applied to value these impacts in a non-monetary approach. The system is planned as a comprehensive instrument, able to solve a variety of multi-criteria problems, in different fields, therefore enhancing the efficiency of the designer's decision making process and possibilities.