Based on analogy between the charging and discharging of humans' tolerance to overheating stimuli and that of charge in an electrical capacitor, this paper proposes a simple mathematical model for predicting overheating risk given a set of measured / simulated environmental conditions. The model is analytically based, but uses coefficients to empirically tune its charging / discharging time constants to a given population and situation. The paper goes on to present an extension of this model, which takes into account occupants' actions to adapt their personal and environmental characteristics to alleviate discomforting stimuli: more specifically the probability with which such actions will take place and the corresponding impact of these actions on occupants' thermal satisfaction.