Materials composition or energy characteristic - What is more important in environmental life cycle of buildings?

The energy requirement of buildings is directly related to the technology of their construction and the type and amount of used building materials. The higher the cost of purchasing materials, especially insulation materials is, the lower the expected costs of use are, which is connected with lower energy losses. The dilemma between the increased building costs and the higher costs of use is rather common, and the investors usually make their decisions based on the economic criteria. However, in the era of sustainable building and a tendency of introducing environmental factors into the decision making processes, the environmental costs related to the individual decision making scenarios have become a more frequent additional criterion accompanying the process of resolving of such a dilemma. Within the scope of this article, the results of a comparative environmental Life Cycle Assessment (LCA) of four functionally equivalent buildings with different material structure, construction technology and energy standards have been presented. The main goal of the analyses has been providing the answer to the question, what is the key element, from the environmental point of view, in the life cycle of buildings and is it a common element regardless of the technology of construction and the energy standards.