Design issues concerning circular economy assessment methods at the product level: a comparative analysis through a case study of a mobile tiny house

Sustainability evaluations are increasingly relevant in the design of products. Within sustainability-related frameworks, circular economy (CE) has gained attention in the last few years, and this has vastly affected design, leading, for example, to design for circularity. This article deals with the wide range of product-level CE assessment tools, out of which some are applied to a case study from the building sector, namely a tiny house made with hemp bricks. Attention was specifically paid to those methods through which a single circularity indicator could be extrapolated. Overall, the objective of this work is to study the convergence of existing CE assessment methods in providing consistent circularity performances. The results show similarities in the overall circularity scores despite differences in the variables used to achieve that final score. Thus, despite the lack of standard methods, the results suggest that many of these tools are sufficiently interchangeable, also in consideration of consistent indications to improve the circularity of the tiny house. This means that consistent inputs are provided to anyone willing to redesign the tiny house with the objective of making it more circular irrespective of the assessment tool used.