We present experimental results of temperature measurements obtained using UOTSes in an office environment over prolonged periods of time (tens of hours). The aim of the experiments was to assess the unattended long-term performance of the UOTSes compared to a conventional reference sensor. Specifically, we examined the relationship between the output frequency and the reference temperature, the degree of scatter, and the presence of any undesired readings. The experiments were conducted both in an open office space and within an enclosure that minimized air movements around the UOTS.

While some undesired artifacts were observed, the output frequency of the UOTSes closely tracked the reference temperatures for the majority of the experiments conducted over extended durations (including overnight, weekends, and even Christmas periods). Notably, both the conventional sensor and UOTS readings exhibited increased scatter when removed from the enclosure. This behavior was consistent with previous data reported by various researchers.

These results demonstrate the viability of using UOTSes for temperature monitoring in dwellings. The unique advantages of UOTSes include their ability to sense temperature across complete ultrasonic pathways (rather than at a single point like conventional sensors), their rapid response to changes due to the air between transducers serving as part of the sensor, and their high resolution (approximately 50 Hz per degree Celsius).