The Evaluation of Indoor Comfort. Analysis of the Literature and Methodological Proposal

In recent years, indoor comfort has gained more and more importance among researchers and actors in the building sector, and the side effects of the COVID-19 pandemic (especially smart working) have accelerated this process. Its evaluation considers aspects related to air quality, thermal, visual, and acoustic comfort. This work proposes a literature analysis of some existing methods for assessing indoor comfort both from a non-monetary point of view, with reference also to the green building rating system, and from a monetary point of view. As regards the non-monetary evaluation, some works were analyzed. In particular, the method is based on the evaluation of uncomfortable hours, the energy performance and occupant productivity method (EP-OP method), the TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) technique, the multi-attribute analysis, and the ELECTRE (ELimination Et Choice Translating Reality) method. Among the rating systems, LEED (Leadership in Energy and Environmental Design), ITACA (Istituto per l’innovazione e Trasparenza degli Appalti e la Compatibilità Ambientale), WELL, and BREAAM (Building Research Establishment Environmental Assessment Method) were considered. As regards monetary valuation, the hedonic pricing method and global cost criterion were considered. The contribution also offers a methodological proposal of the application of the conjoint analysis using the discrete choice experiment technique for evaluating the economic value of indoor comfort. Using this technique, a questionnaire is prepared and the respondents choose among different alternatives (a combination of the different technological solutions and related additional cost compared to the basic solution of reference), proposed each time in pairs. For each of the attributes (thermal, visual, acoustic, air quality, and cost), the levels have been identified, which are related to the technological solutions as regards the aspects of comfort and related to the additional cost compared to the basic solutions that can be adopted as regards the attribute of the cost. The results of the analysis represent the estimate of the willingness to pay for the improvement of indoor comfort, thus attributing a monetary value to it. It is believed that attention to comfort in buildings, especially in residential and office buildings, is today an increasingly central need and the development of existing methodologies represents an important prospect for research in the immediate future.