# Alternative Method for Predicting Thermal Response in Two-Layer Systems
## 4 Discussion
It should be noted that the results of the thermal audit differ slightly from those of the R\({}_{\text{ct,tot}}\) mapping. This was due to the R\({}_{\text{ct,tot}}\) results being shown as relative changes to the starting value at the 0 mm microclimate thickness, whereas the results of the thermal audit were conducted using the absolute R\({}_{\text{ct,tot}}\) values. This notably impacted the trends at the 0 and 5 mm air layer thicknesses. The trends became more coherent as the microclimate thickness increased. For example, in Figure 3, it was observed that, in the open-spacer design, the insulation peaked at 5 mm in all the samples and then decreased below theinitial value at 0 mm at the 10 and 25 mm microclimate thicknesses. In Figure 9, it can be similarly observed that 5 mm required the highest sweat rate in the open-spacer design, and at 10 and 25 mm, less sweating was required. To express this numerically, sample B had the following sweat rates as the microclimate thickness increased: 294 g/h/m\({}^{2}\), 352 g/h/m\({}^{2}\), 299 g/h/m\({}^{2}\), and, finally, 247 g/h/m\({}^{2}\). Similarly, sample D exhibited the following values: 326 g/h/m\({}^{2}\), 358 g/h/m\({}^{2}\), 286 g/h/m\({}^{2}\), and 229 g/h/m\({}^{2}\). The results of each should be contextualized but overall similar trends are present between the R\({}_{\text{ct,tot}}\) mapping and thermal audit. Overall, the results of the predicted thermal response demonstrated that not only were the individual levels of all the parameters important but also the levels of the other parameters. Therefore, when assessing thermal loads, all specifications of the environmental parameters must be considered, even when only assessing one parameter. For example, the presence of ventilation influenced whether sweating was even needed for the different samples (Figure 6). However, this is also dependent on the microclimate thickness, as even a difference of 5 vs. 10 mm can greatly influence the predicted physiological response. At low ambient wind speeds (\(\leq\)0.5 m/s), the microclimate thickness and level of ventilation were crucial. But when the wind speed was increased to 1.3 m/s, the air permeability of the material began to exhibit a stronger influence on the thermal load. For future work, the heterogeneity of the microclimate thickness can be incorporated to provide a stronger representation of the thermal response. The results of this analysis were consistent with the findings of [PERSON] et al. [10], which observed that the ventilation rate had a strong effect on the heat loss. Similarly, it was also observed in [PERSON] et al. 's study that the effect of the clothing size (i.e., microclimate thickness) varied with the ventilation rate. [PERSON] et al. [14] also found that as the ventilation and microclimate thickness increased, so did the heat loss, but the exact values of these metrics were not specified. [PERSON] et al. [5] also found that garments higher in air permeability had better performances when conducting experiments with human subjects. However, the microclimate thickness and ventilation levels were not specified in this work. [PERSON] et al. [3] also found that a higher metabolic rate was better suited to outline differences between garment ensembles, but not much information is given on the material construction and environmental parameters, so it is difficult to quantify the results overall. But, generally, the results of this study agree with those of previous studies conducted on more complex measurement systems, showing that the sweating guarded hot plate can be used to predict the performances of different samples by incorporating different levels of wind speed, microclimate thickness, and ventilation.