In this study, the following steps were performed to weigh the importance of the sustainability evaluation criteria using the AHP technique:

• Step 1: An evaluation criterion was proposed by creating a hierarchical structure. The highest-level goal was to evaluate the sustainability of mid- to long-term retrofitting plans. The structure was divided into environmental, economic, and social criteria and includes each substandard.

• Step 2: A pairwise comparison of the evaluation indicators was performed by experts using Saaty's 1‒9 relative measurement scale. The relative importance of the evaluation criteria was calculated by constructing a pairwise comparison matrix. Table 2 presents an example of pairwise comparison, in which a certain expert considered the environmental criteria to be three times more important than the economic criteria.

• Step 3: The scores of alternatives for evaluation criteria were calculated by conducting a preference survey for each alternative. For example, a questionnaire that included the preferences of alternative evaluation criteria was administered, in which the experts assigned quantitative scores for each alternative.

• Step 4: The relative importance of the evaluation criteria was calculated by obtaining the eigenvector of the pairwise comparison matrix of the evaluation criteria, and the scores of the alternatives were calculated using this eigenvector and the normalized relative importance.

• Step 5: To examine the reliability of the answer, the CR was calculated and ensured to be lower than 10%.