Are new buildings warmer (when first built)?
One must ask how it is that the thermostats know they are installed in a building with materials that are still curing and drying? They don't. 18°C on a thermostat is the same regardless of a building's age. 
The students may be noticing that the new building is less drafty than the old. A lack of drafts will make a room seem warmer than a similarly heated, but drafty room.