We would not buy a house having windows but no ventilators, as there will be no cross ventilation of air inside the room. Fresh cool Air entering the room through window, gets heated through human and other household activities like breathing, cooking and become lighter. This warm air rises up inside the room. If there is no ventilator near the roof, the warm air will have no passage to leave as the level of window is quite low from the level of warm air. This will increase the room temperature as well as humidity inside leading to human discomfort.
