Windows should have wood or aluminum frames. Aluminum can be reused, free of toxins, energy-saving, cost-effective and free of cancer causing substances. The size of windows can be adjusted in relation to the mass of walls and floors that receives direct or indirect light. Place roof overhangs, canopies or awnings to shade your room from excessive heat. Try to determine the direction of prevailing winds and use casement windows on these areas for it can help hollowing out air that can give natural ventilation.