  The COVID-19 pandemic has brought profound change in the daily lives of a
large part of the global population during 2020 and 2021. Such changes were
mirrored in aspects such as changes to the overall energy consumption, or long
periods of sustained inactivity inside public buildings. At the same time, due
to the large proliferation of IoT, sensors and smartphones in the past few
years, we are able to monitor such changes to a certain degree over time. In
this paper, we focus on the effect of the pandemic on school buildings and
certain aspects in the operation of schools. Our study is based on data from a
number of school buildings equipped with an IoT infrastructure. The buildings
were situated in Greece, a country that faced an extended lockdown during both
2020 and 2021. Our results show that as regards power consumption there is room
for energy efficiency improvements since there was significant power
consumption during lockdown, and that using other sensor data we can also infer
interesting points regarding the buildings and activity during the lockdown.
