## 5 Results and Discussion
### Measurements and Interpretation
As expected from the interpretation of the pure sensor characteristics (compare Figure 8), the faster reaction time of the signal by the Nodon sensor is also advantageous for control. Despite this, control is still possible when using the temperature measurement by the Pressac sensor. Nonetheless, the Pressac sensor is installed usually in our project because of its ability to measure further relevant data. Another comparison of temperature data is given in Figure 10, with respect to the orientation of the rooms in which the measurements were taken. The temperature measurement by sensor three was taken in a room whose windows are oriented towards the south-west. The measurement by sensor four was taken in a room on the opposite side which, moreover, is close to a small forest. The weather data shown in this figure is based on _Deutscher Wetterdienst_ (DWD) [82; 83]. During the two days where the peaks of temperature were significantly lower, one can see relevant cloudiness and reduced global radiation. Despite being measured in a living lab with unmeasured influences, the huge effect of solar radiation can be seen. In addition to this, another possible influence is the position of blinds, which was not recorded at that room within the interval. As mentioned earlier, we have designed our measurements to give us several different data points that we can use for different scientific applications and to derive different quantities of interest. Including also different buildings with different construction types and construction dates allows us to compare CO\({}_{2}\) concentrations under different circumstances. An exemplary comparison between measurements taken in an older building (sensor one, blue line) and a newer building (sensor two, red line) is given in Figure 11.  
First of all, measurement noise is visible in both curves. Additionally, we conclude two main effects from the curves here. While in the older building, the concentration falls to a ground level of approximately 700 ppm, this value is only reached twice in the entire time span visualized for a short amount of time in the measurement data taken in the newer building. The level also drops very slowly throughout the day of the eleventh of February. We conclude that the air infiltration rates differ significantly between the  
Figure 10: Comparison of temperature measurements in two rooms with different orientations and radiation data. buildings. Secondly, changes in CO\({}_{2}\) concentration indicate differing manual ventilation patterns. This suggests potentially significant differences in occupants' behavior. Finally, our retrofitted sensor and control network allows for in-depth analysis of energy-related user behavior patterns. In Figure 12, the electric power consumption of one office located at the JSL is shown together with the output signal of a ceiling-mounted presence sensor. From a simple analysis of the data, several observations can be made (from left to right in Figure 12). First, there are intervals of ICT communication interruptions, which are indicated by gaps in the measurement data. Secondly, inter-day and weekend periods can be observed by analyzing the occurrence of absence and electric power drawn from the sockets. In that regard, it becomes obvious that a certain stand-by consumption remains present also during, e.g., weekends. This may be a result of loads such as screens, printers, or other devices that, out of convenience, are usually not un-plugged, even during longer periods of absence. During periods of occupancy, differing patterns are observed. In week-day pattern A, an electric load in the range of 60 W to 75 W occurs for roughly two days,  
Figure 11: Comparison of CO\({}_{2}\) concentrations in two rooms in different buildings  
Figure 12: Data obtained through the advanced sensor and control network, including presence detection (top) and electric power measurements on two socket strings (center and bottom) for one office located in the JSL. Important observations are highlighted.