Thereby he presented that when using sensors to detect occupants, it is important to have the following properties of the sensor:

• People are the dominant source of change (or at least significant)
• Constant and uniform source strength (or at least predictable)
• Ability to predict the other sources
• Minimal buffer effects

In general, the most promising sensor for occupant detection is the CO2 sensor, as occupants are the primary source and most other sources are predictable. In contrast, VOC sensors are unsuitable as unknown sources can influence them, and they are sensitive to too many different parameters, such as temperature, humidity, and particles.