Evaluation of the Environmental Impact and Financial Cost of Buildings in the First Design Phase

Since most important design decisions are taken during the first design phase, an evaluation ofthe total environmental impact is necessary at that moment. A first step in that direction is takenby the Flemish government through the introduction of the Energy Performance Norm (EPN) fromJanuary 2006 on. The EPN evaluates the overall energy consumption of buildings during the usephase instead of looking at thermal insulation and compactness only. However the environmentalimpact is not only caused during the use phase of the building, moreover not only energyconsumption, but also emissions, depletion of resources, land use, etc. contribute to theenvironmental impact.A methodology is being developed to evaluate all these aspects during the first design phase. It isbased on different existing methods: life cycle assessment, life cycle costing and the elementmethod. Moreover the financial cost is incorporated in the evaluation since it is often an importantdecision parameter. The marginal effects of the environmental and financial costs are used ascriteria for ranking possible choices. The methodology will be described and illustrated by a casestudy.