A macro-component approach for the assessment of building sustainability in early stages of design

• This paper presents a novel life cycle approach for buildings in early design stages.
• The lack of data in early design stages is addressed by the macro-components approach.
• The approach considers life cycle embodied impacts and energy needs of buildings.
• The approach is consistent between design stages, despite the lack of early data.
• It provides guidance to designers in the pursuit of long-term building efficiency.

In the framework of the European research project SB_Steel, a new life cycle methodology was developed aiming at the evaluation of life cycle impacts of buildings in the early stages of design. The proposed approach includes the estimation of the energy needs of the building during the operation stage. The early stages of design have the higher influence on the life cycle performance of the building; however, in these stages the availability of design data is often limited. Moreover, the estimation of energy needs is usually based on a performed-based approach, requiring a full definition of the building design.In the proposed methodology both problems are addressed by the macro-component approach, which provides a range of pre-defined construction solutions for the main components of a building, integrating life cycle embodied data. The approach enables a simplified estimation of the life cycle environmental performance of a building based on limited design data and provides aid for decision making in relation to the use of different materials and construction solutions aiming to lower life cycle impacts and lower energy consumption.The proposed approach is illustrated by a case-study, in which a residential building is assessed in the early stages. Finally, based in complete data, an advanced analysis of the building is performed in order to discuss the limitations of the developed approach.It is shown that the limitations introduced by the simplified approach are not relevant and that, even with lower availability of data, the guidance provided by the methodology is adequate.