The orientation of a large expanse of glass in a house is important. Improperly positioned, it can cost precious fuel dollars, whereas good orientation can minimize heat lost in the winter and gained in the summer. The best direction to face is south, to make good use of solar energy. Since the sun is low in the southern sky during the winter, orienting any glass in that direction will allow light to shine through and help heat the home. During the summer, the sun is higher in the sky, and an overhang from the roof will shield the glass from direct sunlight. According to the passage, large expanses of glass should be positioned to