This paper reports a study on the impact of different usage patterns of an automated blinds system on the energy consumption for heating and cooling in a Dutch office building. A five-month observational field study in 40 offices resulted into a dataset on the blinds usage of four types of blind users. This data was used to simulate the effect of the blinds usage on the energy consumption for heating and cooling. The results of the field study show that a majority of the building occupants switched off the automatic mode of the blinds system permanently. The simulation results indicate that this significantly impacts the energy consumption in the building. The total daily average energy consumption for heating and cooling was significantly lower for occupants using the automatic mode than for the three groups of manual users (871W/day versus 2573W/day; T=-5.98, p=0.000).