## 3 Results and Discussion
### Final Discussion of Key Findings  
From the analysis developed in Section 3.1, it follows that the best results, in terms of energy consumption reduction, are achieved by double-glazed windows with metal or PVC frames. At the same time, these configurations meet the requirements for indoor comfort. Consequently, they contribute to attaining the energy-thermal comfort binomial within the framework of sustainability in nZEBs.  
Indoor air temperature is the main parameter involved in human comfort assessment and, therefore, this has been taken as the only control parameter in numerous thermal comfort assessments and microclimate analyses [48]. There are very few evaluations that consider both indoor temperature and energy consumption as control parameters [48]. One example can be found in [49], where a comparison is made of the two parameters obtained for the same building model by two different Building Energy Performance Simulation (BEPS) tools (Design Builder/Energy Plus, and IDA ICE). This study considers a scenario with a small window (4.9 m\({}^{2}\)) and another with a large one (7.4 m\({}^{2}\)).  
The present research work compares the results of primary energy consumption for cooling within the operating temperature ranges corresponding to the optimal indoor comfort level for different building typologies and from multiple simulations carried out for different configurations in the design of frames, glass, and shading systems in window openings.  
While an experimental investigation on thermal comfort in an office building located in a hot climate [28] provides a general recommendation to use isolated aluminium window frames, from the results obtained in the present study, it is determined that the specific configuration to minimise energy demand is a metal window frame with no thermal bridge break combined with double-pane glass. However, it should be noted that significant energy savings, slightly lower than the optimum configuration, are also achieved with both light- and dark-coloured double-chamber PVC frames in combination with double-pane glass. In this sense, PVC window frames are also competitive with other window frame types in terms of achieving the energy-comfort nexus, and their choice would be justified if other factors are also taken into account, such as economic costs or the degree of resistance to corrosion and oxidation.  
In view of the results of this study, the greatest energy savings are achieved with GL3 glass, which is characterised by its low emissivity (see Table 5). While it is true that low-emissivity glass is highly recommended for the optimisation of both cooling and lighting efficiency in buildings located in hot climates [30], this study specifies the characteristics of the glass, such as the thickness of the layers, the solar factor, and the thermal transmittance in both vertical and horizontal position (see Table 5), as well as the type of frame with which it should be combined (see Table 6) to minimise primary energy demand and meet indoor comfort conditions. In this sense, the use of low-E double pane glass is recommended in single-family dwellings located in hot climates.  
As shown in Section 3.2, energy consumption is lowered with the different types of fixed shading systems considered, except for the extreme system WSHA-6, based on fully closed blinds during the summer period, which increases consumption, as it hinders the expulsion of the heat generated inside the living space. One solution found in the literature to reduce cooling energy needs is to use mobile shading devices with seasonally adaptable solar transmission coefficients [32]. However, these devices are not considered to be the most suitable solution, as they need to be modified depending on the weather conditions. In this sense, the results obtained in the present study show that the fixed 75 cm deep horizontal and vertical shading system is able to minimise energy consumption and ensure comfortable indoor conditions.