One of the recognized primary paths to decarbonizing the building stock and combating climate change is the move towards smart buildings. In light of this, the majority of governments and policymakers advocate retrofitting existing non-smart buildings. However, the smart retrofitting (SR) process has various well-known complexities, such as significant investment costs and technical difficulties, which make the SR decision-making process extremely challenging. As an essential step for establishing a tool to aid this process, a questionnaire survey was conducted to shortlist the most significant SR decision-making criteria from five categories of applicable criteria: (1) financial; (2) technical; (3) user comfort and convenience; (4) environmental; and (5) legal, safety, and security. Facility management professionals in Hong Kong were invited to participate in the survey and their responses were statistically analysed. According to the survey results, 20 of the rated criteria were regarded by the respondents as important or highly important. The majority (40%) of these 20 criteria belong to the ‘technical’ category. The results can help decision-makers such as building owners, investors, and facility managers understand the ranking order of the criteria for prioritizing SR decisions. Future works for establishing the intended SR decision-making tool are also outlined.