The aim of the proposed research project is to develop uniform methodological guidelines for life cycle assessments (LCA) in analogy to the methodological guidelines for photovoltaics developed in IEA PVPS Task 12. Life cycle assessments are becoming increasingly important for political decisions and regulatory instruments at national and international level, as well as for individual consumer decisions. To ensure that these decisions are based on comparable results and a robust data basis, uniform and harmonised methodological guidelines are needed. To this end, there have been various Product Environmental Footprint (PEF) pilots at the European level for different products with the aim of harmonising the accounting approaches. For solar heating and cooling systems, no corresponding methodology guideline exists yet, in contrast to photovoltaics with a PEF pilot and the LCA methodology guideline developed in IEA PVPS Task 12.