Buildings energy retrofit valuation approaches: state of the art and future perspectives

The European Directives 2010/31/EU and 2012/27/EU identified the buiding sector as a key sector to achieve the 20-20-20 targets (and those set for 2030 and 2050) and identified existing buildings energy retrofit as a fundamental driver to promote development and create opportunities for employment in this sector which is still affected by a severe economic crisis. Buildings energy retrofit is a complex process involving a great number of decision variables and issues related not only to technical and technological aspects, but also to environmental, social and cultural aspects. This topic is widely debated in literature. There are several contributions on energy consumption modeling and evaluation as well as many authors addressed the impacts of retrofit strategies on CO2 emission reduction. There exists also a conspicuous strand of literature on the methodologies to evaluate different retrofit strategies according to their economic, environmental and social effects (e.g., multi-criteria analysis, life cycle costing and assessment, econometric models, etc.). Nonetheless, there is a lack of contributions that provide a systematic literature review and a classification of most relevant papers on the most innovative and multidisciplinary valuation approaches. This paper presents a systematic literature review, and aims to define the state of the art on valuation approaches of existing buildings energy retrofit. According to a dynamic systematic review protocol, we identified the most relevant contributions and we provide a synoptic table, which summarizes methodological and descriptive aspects and allows for identifying potential gaps in the literature and future developments.