Resumen
In order to reduce the use of energy in buildings, it is necessary to make changes in the society paradigm, not only changes in the way buildings use energy. It seems appropriate to analyse the savings that can be obtained by simple actions related to the implementation of good practices for passive conditioning, for which no economic investment are required. As a zero-investment action, the possibility of moving the school schedule to the period of the day in which the exterior temperature is lower needs to use energy to maintain the comfort condition inside the building is analyzed. Simulations of nine activities about moving school schedules and close the shutters in a teaching centre building located on the Spanish climatic zone D3 are carried out. The percentage of savings when the teaching centre imparts classes from 14:00 to 21:00 during October to May and from 7:00 to 14:00 during September closes the shutters in the summer period and in winter evenings is the 50%. The ?6,120 of savings that are obtained annually with this activity could be an interesting economic injection that allows to undertake future investments in the school, and with it achieving the objectives sought with circular economy.