This thesis studies the new guidelines for designing buildings that are more environmentally friendly, with greater emphasis on the Decree on Green Public Procurement. Recently, new environmental legislation, standards and laws have been adopted, both nationally and internationally. The construction sector consumes 40 % of all materials, 40 % of all energy and produces 35 % of all waste, which is why Slovenia and the European Union promote and develop a variety of environmental solutions in order to ensure more sustainable construction. The thesis first provides definitions of the basic concepts occurring in connection with construction products, in particular of the Life Cycle Analysis and Environmental Product Declaration. In addition, an overview of the ISO 14000 environmental standards, which are intended to provide the elements of an effective environmental management system for businesses, is given. Greater attention is paid to the Decree on Green Public Procurement which has recently entered into force with the aim of reducing the environmental impact and presenting exemplary management of state finances. Following the example of the Decree on Green Public Procurement, 24 different structural assemblies were made, in which different volumes of timber and wood-based materials were used and compared with each other. In the end, the key findings were recorded and a comparison between the prices and the carbon footprint of individual materials was made.