## 3 Results and Discussion
### Delays in Temperature Changes  
Apart from their energy performance, other differences were observed between the two facades. When the outdoor temperature changed, the indoor temperatures changed as well, but not immediately. Figure 14: Thermal transmittance through the test walls based on energy use data and U-value based on material properties. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **U-Value Based on Material** & **U-Value Based on Energy** & **Reduction** \\  & **Properties [W/m\({}^{2}\)K]** & **Use Data [W/m\({}^{2}\)K]** & **Reduction** \\ \hline Room A (lime) & 1.60 & 0.91 & 43\% \\ Room B (hemp-lime) & 0.91 & 0.61 & 33\% \\ Reduction & 43\% & 33\% & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Thermal transmittance through the test walls, based on material properties and based on energy use data. There was a thermal buffering effect that could be observed for both facades. This was most clear in late summer/early autumn, when there were relatively large diurnal differences in temperature, but no heating was required yet, or only sporadic heating took place. In September, the temperature differences between day and night were quite pronounced, but hardly any heating was required yet (see Figure 15). When the outdoor temperature changed, it took a while for the indoor temperature to change as well. For example, on 21 September at 01:50 am, the outdoor temperature was at its lowest at 7.6 \({}^{\circ}\)C. This could be observed in room A approximately 10 hours later, when the indoor temperature was at its lowest at 19.7 \({}^{\circ}\)C. In room B, there was a delay in temperature change compared to room A: the indoor temperature was at its lowest 11.5 hours after the outdoor temperature reached its lowest point. The lowest temperature in room B was then 20.5 \({}^{\circ}\)C, before it went up again. In short, the difference in delay was 1.5 hours, and the difference in indoor temperature was 0.8 \({}^{\circ}\)C, with room B being the warmer room. One day later, on 22 September, the outdoor temperature was at its lowest at 7.1 \({}^{\circ}\)C at 07:14 in the morning. The effect of this low outdoor temperature was observed in room A only 4.5 hours later when the indoor temperature was as low as 19.0 \({}^{\circ}\)C, and heating was required. In room B, the temperature went down to 19.9 \({}^{\circ}\)C, which was at 14:20 am, approximately seven hours after the lowest outdoor temperature had occurred. In addition, in room B, no heating was required. In short, the difference in delay was 2.5 hours, and the difference in indoor temperature was 0.9 \({}^{\circ}\)C, with room B being the warmer room. In addition, no heating was required in room B, whereas heating started in room A when temperatures reached 19.0 \({}^{\circ}\)C.  
In both rooms, TESTO devices (measuring temperature and relative humidity) were installed on the wall surface. Figure 16 shows the indoor temperatures in both rooms as well as the outdoor temperature from 15 to 26 September 2017. During this period, room B did not require any energy for space heating, while room A used 1.1 kWh. Each time there was a low outdoor temperature, the temperature in room A decreased sooner than in room B. During this 11 day period, room B had  
Figure 15: Changes in indoor climate in rooms A and B compared to outdoor temperature during 21–24 September 2017.  
a slightly higher indoor temperature than room A: 20.3 \({}^{\circ}\)C compared to 20.0 \({}^{\circ}\)C, even though room A required some energy for space heating. During the summer months, no energy use was required for space heating. At higher outdoor temperatures, the indoor temperature in room A was consistently a little bit higher than in room B (see Figure 17). Also, at lower outdoor temperatures the temperature in room A was a little bit lower than in room B. In other words, the diurnal temperature variation had a larger impact on room A. This same phenomenon could be observed at even higher temperatures, when outdoor temperatures reached over 30 \({}^{\circ}\)C (see Figure 18).