Adaptive thermal comfort strategies allow to achieve significant savings in the energy consumption of a building. This represents great potential for buildings since it allows to guarantee thermal comfort and reduce energy consumption without the need for economic investments. However, decision-making can make it difficult to implement the most appropriate strategy. For this reason, this chapter analyzes the single criteria and multi-criteria process to determine the most appropriate strategy. For this, fuzzy logic is used. With the fuzzy logic, two expert systems were designed: one for rehabilitation works (affected by the improvement achieved and the investment price) and another for new buildings. These models analyzed four case studies. The results obtained have shown that the systems designed with fuzzy logic have an adequate success rate with respect to the expected decision. Therefore, they constitute an adequate methodology for decision-making with respect to the thermal comfort model. In addition, architects and engineers can make modifications to the structure of the systems to adapt them to different regions.