Main doors or entrances to a south-facing property must be positioned in the center of a south-facing wall or area, according to vastu principles. This is done to align the energy of the home. Entrances to the left of the center point are likewise often favorable. The reasoning is that since the sun enters the house through the west side where it connects with the outdoor living space, having an entrance on the west side helps to draw this energy inside. An east-facing entryway is preferred by some people as it is believed to bring good fortune. However, due to the sunniness of eastern exposures, this doorway should be at least 150 degrees from direct sunlight during the day. A north-facing entryway is best avoided because it tends to lead to problems with cold air entering the home during subzero weather. A south-facing entryway does not present any special problems except to note that it is preferable to have this entrance near the center of the property wall so that the flow of energy is even. An entryway on the southwest corner of the property limits the amount of sun that can reach the interior of the home. A family room or living room must have a window that faces east or west. Windows that face north or south will require covering them with drapes or blinds. This is necessary to prevent negative energy from these directions entering the home.