According to Vaastu the size of room does not affect the fortune of the person living in it. However the direction of the room may affect the fortune of the person living in it. According to the government norms for the size of rooms and keeping in view the health norms, the size of a room should not be less than 9.5 sq meter  in case of one room-house and 9.5 sq metre and 7.5 sq metre in case of  two room-house.