# The Impact of Internal Insulation on Heat Transport through the Wall: Case Study
## 3 Results and Discussion  
### Measurements of Temperature and Heat Flux  
The emissivity of finishing layers of the wall was determined by the comparative method with respect to the reference tape with the known emissivity of 0.96. The emissivity of the inner plaster determined on this basis is 0.92. Due to differences in the emissivity of the individual selected types of facade ceramic tiles, ranging within 0.89-0.93, the average emissivity of 0.91 was determined for a given surface. The temperature of indoor and outdoor air for the measurement No. 1 (the wall without thermal insulation) was respectively \(t_{i}\) = 19.3 \({}^{\circ}\)C, \(t_{e}\) = 2.7 \({}^{\circ}\)C, while for the measurement No. 2 (after applying the insulation from the inside) it was \(t_{i}\) = 17.0 \({}^{\circ}\)C, \(t_{e}\) = -2.5 \({}^{\circ}\)C. The results of thermal imaging measurements before and after the application of the insulation layer on the inner wall (Figure 2) surface are presented in Figure 4, and the results of temperature as a function of distance px are presented in Figures 5-7. Figure 4: Temperature distribution in color scale on the wall surface from the side of heat inflow (**a**) without thermal insulation (**b**) with thermal insulation from the inside. Figure 5: Temperature distribution along the lines Li1 and Li3. Figure 6: Temperature distribution along the lines Li2 and Li4. Figure 7: Temperature distribution on the surfaces Bx1 and Bx2. The analysis of thermographic measurement results before the application of the insulation (Figure 4a) and after the application of the insulation (Figure 4b) for different environmental conditions on both sides of the envelope indicates that there is a change in the character of temperature distribution. It is demonstrated on the diagrams along the lines Li3 and Li4 (Figures 5 and 6). The course of temperature changes along the line Li3 determined from the corner of the outer walls shows that there is a significant reduction of the impact of the geometric linear bridge after the insulation. We can observe a sharp change in temperature on the outer wall surface at the distance not exceeding 0.15 m, followed by its stabilization. Before the insulation, the temperature on the wall surface along the line Li1 stabilized at the distance of about 0.55 m from the corner (Figures 5 and 6). A similar situation can be observed for the line Li2 at the junction between the wall and the ceiling (Figures 5 and 6). The measurements were made at a small angle to the wall surface in order to minimize the influence of reflected radiation. If the measurements had been made at right angles to the surface, they could have been distorted. Based on the information about the distance of the thermal imaging camera from the tested wall and knowing the selected actual characteristic dimensions, lines Li1 and Li3 perpendicular to the curtain wall of the same direction and approximately the same length were determined. Similarly, lines Li2 and Li4 perpendicular to the ceiling surface were determined. When examining the temperature field Bx1 before the thermal insulation, we can observe its slight surface variation (Figure 7). The lowest temperature was recorded in the fragment of the wall-to-ceiling connection. The distribution of temperature on the insulated surface (Bx2) allows to identify connections between individual thermal insulation elements in which a slight decrease in temperature on the inner wall surface is observable (Figure 4). Additionally, a decrease in temperature on the surface of the insulation is observed at the place of the existing mechanical connector (Figure 7). This may be caused by the change of heat conductivity coefficient, although a slight influence of the change in emissivity at this place cannot be ruled out. The heat flux sensor was placed from the inside at the height of 1.0 m above floor level, at a distance of 2.0 m from the outer wall.