Comparison of the Carbon Payback Period (CPP) of Different Variants of Insulation Materials and Existing External Walls in Selected European Countries

The EU "Fit for 55" legislative package provides for the introduction of regulations enabling the achievement of the emission reduction target by 55%. As part of the necessary actions, it is necessary to increase the energy efficiency of existing buildings. To achieve this, there are plans to increase the pace of the modernization of buildings, from 1% to 3% of buildings annually by 2030. However, this must be done with respect to the principles of sustainable development, circular economy and the conservation of buildings. This article presents a comprehensive comparison and calculation of carbon payback period (CPP) for selected insulation materials, combined with selected typical building partitions, and shows how quickly the payback period of greenhouse gases in the production of insulation materials is completed. Individual insulation materials (stone and glass wool, expanded polystyrene (EPS), extruded polystyrene (XPS), polyurethane (PUR) and cellulose) were analyzed in relation to different types of walls (seven types-including solid wall, diaphragm wall, large panel system (LPS), and concrete), in different locations (Poland, Germany, Czech Republic, Austria, Finland, Europe) and for various energy sources (electricity, gas, oil, biomass, district heating). After taking into account the carbon footprint embodied in the insulation materials, along with the potential reductions in the operational greenhouse gases emissions, the carbon payback period (CPP) was determined, resulting from the use of a given technology, insulation material and location. By comparing the CPPs for different insulations, this paper shows that the results vary significantly between EU countries, which have different embodied carbon factors for energy sources and materials, and that there is still a serious lack in the availability of reliable environmental information, which can limit research results.