INFLUENCE OF THERMAL INSULATION ON THE ENERGY BALANCE FOR COLD-FORMED BUILDINGS

Two major factors contribute to the sustainabilily of buildings: material efficiency and energy efficiency. Material efficiency relates to the use of environmental-friendly materials and to the minimization of construction waste materials, either during construction and at the end-of-life stage of the building. Energy efficiency is currently understood as the optimization of the energy used during the operation stage of the building. This entails the energy needed for heating, cooling, lighting, etc. Often in order to improve the energy needs of a building, more insulation material is used, thus leading to a trade-off between embodied energy and operational energy. It is the aim of this paper to analyse and discuss the balance between the embodied energy and the operational energy for various levels of insulation, over its life cycle. The operational energy is estimated based on the simplified approach provided by the Portuguese Code of practice. The estimated operational energy is then balanced against the life cycle embodied energy of the system. Finally, the simplified approach for the calculation of the operational energy is confronted to more sophisticated dynamic simulations using the software EnergyPlus.