A systematic review of the life cycle cost estimation of upgrading buildings for sustainability.

In this study we have identified and evaluated literature related to refurbishment, renovation, retrofit and/or repair in the construction sector. We present a bibliometric evaluation along with a systematic critical review to identify materials used in upgrading buildings. We located 47 such publications. We found that more studies focus on renovation than those that address refurbishment, retrofit or repair, with respective counts of 19, 17, 12 and 10. The number of publications has fluctuated over the past few years. In some years, such as 2015, 2018 and 2023, an increasing number of studies were published, while there was a decline in 2015 to 2017 and 2020. Notwithstanding this, spikes in publication numbers occurred multiple times. Furthermore, the citation trend was generally upwards, suggesting that research in this field has gained increasing academic attention and influence over time. The originality of this study reveals the uncertainty of researchers in selecting cost evaluation methods when upgrading buildings. The trend suggests that further innovation and clarification is needed to enhance cost assessment methodologies. Evaluation of system boundaries revealed that most studies do not consider the end-of-life stage when evaluating different materials to upgrade buildings. To achieve an optimum building upgrade solution, single-objective optimization such as evaluating cost or LCA is insufficient, and multi-objective assessment methods need to be considered. Further research is needed to determine which upgrading strategies can effectively influence costs in optimization energy strategies.