Life Cycle Thinking (LCT) applied to residential heat pump systems: A critical review

•A critical review of selected contributions on the sustainability of heat pump systems using the Life Cycle Thinking tools.•A discussion on methodological assumptions and main results.•Recommendations on how to improve the sustainability of heat pump devices from a life cycle thinking approach.•Apart from the operational stage, other aspects need to be considered in the total life cycle of a heat pump system. Heat pump technology is widely considered to be one of the promising opportunities for energy-efficient and low-carbon solutions for buildings and construction. However, sustainability is not always an intrinsic feature of all heat pumps. According to the Life Cycle Thinking approach, to assess the complete sustainability of a technology, a direct evaluation of the environmental, economic and social aspects over the entire life cycle is needed. Due to the growing interest in this technology, the present review summarizes the existing contributions on the sustainability of heat pump systems for residential heating and cooling using the Life Cycle environmental and Social Assessment and Life Cycle Costing. The main results are highlighted, then the data input, methodological assumptions and evaluation criteria are analyzed. The study reveals how to improve the sustainability of HP devices from a life cycle thinking approach.