Mechanical systems (heating, cooling, and ventilation systems) allow actively controlling the indoor environment in buildings. However, buildings can also be naturally conditioned or conditioned in a hybrid way (benefiting from both natural ventilation and mechanical ventilation in different times of the year or day, also known as mixed-mode). Several studies showed that people have different thermal perception, acceptability and preference depending on several factors, including the building conditioning type (mechanical, natural or mixed-mode). This has also been the essence of the “PMV vs. Adaptive thermal comfort” discussion. This study summarizes the main international thermal comfort standards in terms of their specifications for adaptive thermal comfort model application, and uncertainties that can create challenges and limitations when implemented in building and HVAC system control.