Environmental Impact of Buildings Heating Systems: Renewable Energy Sources and Energy Hub

In the current context related to the environmental impact of buildings, in the field of heat generation and consumptions, there is a multitude of approaches following the main axe—processual sustainability. Within the chapter, the representative typologies of buildings as energy consumers, along with their related heating systems are analyzed, and the possibilities of energetic optimization, in order to reduce the environmental impact, are highlighted and assessed. The chapter includes general notions in the field, current and prefigurative stages of the future sustainable energetic concept and the importance of stepping up the optimization process to reach them, in the case of existing heating systems. The concepts of conventional and renewable thermoenergetic hub are presented. The modern concept of energy hub, which allows the correspondence of a single energy output, the buildings’ heat demand, with several energy inputs, associated with various energy carriers—conventionals, renewables or alternatives, is analyzed from the energetic and environmental point of view. The performance indicators are defined within the frame of the renewable energy based thermoenergetic hub. The representative indicators regarding the environmental impact, the energy and carbon footprints are highlighted. Based on targeted indicators, the possibilities of decarbonisation of the thermoenergetic systems in the buildings’ sector, particularly the increase of the energy efficiency of the buildings and the related heating systems are analysed regardfully for the environment. A case study on the carbon environmental impact of heating systems is presented, followed by discussion and conclusion.