## 1 Introduction
In this regard, users of residential buildings can adopt adaptive strategies limiting the energy consumption of HVAC systems [35; 36]. Thus, the use of such new adaptive comfort models to adjust setpoint temperatures (i.e., adaptive setpoint temperatures) of buildings is an opportunity to guarantee important energy savings without influencing users' thermal comfort. The possible energy savings by implementing such models have been investigated by several research studies. In a first study, [PERSON] et al. [37] analyzed the energy saving achieved by applying the thermal comfort model from kennisinstituut voor de installalesector (ISSO) 74 [38]. The use of the lower limit of such standard achieved an energy saving of 74%. Later, [PERSON] et al. [39] carried out another study with this approach. In their work, the authors analyzed the application of the adaptive comfort model to the operational conditions of air conditioning systems in an office building. The results showed the possibility of using the adaptive thermal comfort model with 87% of users satisfied. However, recent studies have focused on the energy savings which can be achieved in residential buildings. [PERSON] et al. [40] studied the variation of setpoint temperatures in three residential buildings located in various cities in Spain. Setpoint temperatures monthly varied by using the adaptive thermal comfort model from American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 55-2017 [41]. The energy consumption of the case studies analyzed was reduced between 20 and 80%. Likewise, in a recent study, [PERSON] et al. [42] studied the application of adaptive setpoint temperatures in a residential building. The analysis was conducted in the same cities on which the study by [PERSON] et al. [40] was based. The energy consumption was saved between 10 and 46% according to the type of climate in which the building was located. In another study, [PERSON] et al. [43] evaluated different approaches to use the thermostat, including the ASHRAE adaptive comfort model. This analysis was performedon residential buildings in five United States cities (San Francisco, New York City, Phoenix, Miami, and Fairbanks). The results showed savings of up to 54% with the adaptive model power consumption. Finally, [PERSON] et al. [44] analyzed the influence of the alpha value used to calculate the prevailing mean outdoor temperature with adaptive setpoint temperatures. The results showed deviations of up to 0.47 and 1.30% in heating and cooling energy consumption, respectively. Nevertheless, the various research studies related to the application of adaptive setpoint temperatures present several knowledge gaps. The first knowledge gap is related to the tolerance of applying such limit values. Under actual application conditions, users are likely to have limitations to reach the limit values of the adaptive comfort standards. In such standards, the increase in limit values means a decrease in percentage of acceptability of the category. It is also fundamental to consider the influence of users' habits. In this regard, it is worth stressing that the adaptation capacity of the occupants' thermal comfort usually has asymmetric trajectories [45]. Users more used to the use of HVAC systems will have therefore more difficulties to increase the limit values of the operative temperature than those not using such systems [45]. For this reason, this study analyzed various tolerance ranges in the adaptive thermal comfort model used in setpoint temperatures. The study was focused on new buildings as this type of constructions is where users could have a greater demand in thermal comfort limits. To do this, the amplitude of comfort limits was reduced by intervals of 0.25 \({}^{\circ}\)C, and consequently, the amplitude of the comfort zone was narrowed to a total of 0.5 \({}^{\circ}\)C in each interval by increasing the tolerance variable. Furthermore, other three important gaps of the previous studies have been tackled in this research.