## Materials and Methods
### Experimental Tests  
TCI C-Therm equipment was used to assess the thermal properties of the materials used. This was based on the modified transient plane source (MTPS) technique following ASTM D7984-16 [21]. Thermal conductivity and thermal effusivity were measured using a one-sided heat reflectance sensor that applies a momentary constant heat source to the sample. Both thermal properties were measured directly in a short time (see Figure 1). Three samples of layer 1 (Figure 1a; GWG) and layer 4 (Figure 1; GWP) were tested, and we performed a round robin test for the material of layer 3 (Figure 1b; LWMA). We took five measurements for each sample.  
Thermal tests were performed using a 1 m\({}^{2}\) wall that was built and placed in a climatic air-conditioned system that controlled relative humidity (RH) and temperature conditions. The air-conditioned system was joined to a climatic box (hot-box) with a 1 m\({}^{3}\) inside volume, where the desired thermal conditions were provided. The wall tested was built and placed over a steel frame and joined to the hot-box, as shown in Figure 1d. The perimeter of the wall has been thermally insulated with low thermal conductivity foam in order to  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Material** & **Layer ID** & **Acronym** & **Thickness (m)** & **Wall Section** \\ \hline Gypsum-Weber & & & \\ grueso \({}^{\text{\textcircled{R}}}\) & 1 & GWG & 0.015 & \\ Lightweight brick & & & \\ Airblock 25 \({}^{\text{\textcircled{R}}}\) & 2 & LWBA25 & 0.250 & \\ Lightweight & & & \\ mortar-Aslione \({}^{\text{\textcircled{R}}}\) & 3 & LWMA & 0.060 & \\ Gypsum-Weber & & & \\ clima \({}^{\text{\textcircled{R}}}\) & 4 & GWP & 0.015 & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Summary of wall materials’ thickness and position.  
avoid lateral heat losses. Sensors at different locations were used to measure temperature, relative humidity, and thermal fluxes. Sixteen SHT75 capacitive sensors and one Sensirion EK-H3 datalogger were used to measure the temperature and relative humidity, while four Hukseflux HFP01 sensors and four LI-19 data-loggers were used to measure heat fluxes through the wall. The locations of the sensors are shown in Figure 2.  
Steady-state thermal transmittance tests were carried out by maintaining a constant temperature (53 \(\pm\) 0.5 \({}^{\circ}\)C) and varying the humidity conditions from 30% to 70% inside the hot-box. The constant laboratory conditions were a temperature of 23 \(\pm\) 2.5 \({}^{\circ}\)C and a relative humidity of 70 \(\pm\) 2.0%.  
The transient thermal transmittance tests were carried out under constant outdoor conditions of relative humidity of 70% inside the hot-box and 70% outside as well as a variable temperature following a sinusoidal law between 10 and 37 \({}^{\circ}\)C with a cycle time of 24 h and a minimum number of 4 complete stabilized cycles. The laboratory indoor conditions were 25 \({}^{\circ}\)C \(\pm\) 2.5 \({}^{\circ}\)C and 70% RH constant values. Two test directions were considered (see Figure 2). In Direction 1, as shown Figure 2a, Layer 1 was placed on the inside of the hot-box (outdoor conditions) and Layer 4 was in contact with the outside air of the laboratory (indoor conditions). In Direction 2, as shown Figure 2b, Layer 4 was placed on the inside of the hot-box (outdoor conditions) and Layer 1 was in contact with the outside air of the laboratory (indoor conditions).  
Figure 1: Thermal conductivity tests: (**a**) GWG; (**b**) LWMA; (**c**) GWP; and (**d**) experimental set-up.