Window shades come in many different sizes and shapes, and several different designs exist. During long, hot summers, window shades are a necessity for any inhabitable home. They provide safety, security, and cool air. Two types of shading exist, internal and external. External shading is more desirable due to its higher energy efficiency. However, internal shading blocks out more of the rays. Now why in God's name did I just waste 15 minutes defining a friggin windowshade????