Boarding schools substitute school to home, but little is known on the effects this substitution produces on students. We present results of an experiment in which seats in a boarding school for disadvantaged students were randomly allocated. Boarders enjoy better studying conditions than control students. However, they start outperforming control students in mathematics only two years after admission, and this effect mostly comes from strong students. Boarders initially experience lower levels of well-being but then adjust. This suggests that substituting school to home is disruptive: only strong students benefit from the school, once they have adapted to their new environment.