The front door of a house can be equated to the mouth of a human being. You open your mouth only while eating or drinking. Similarly, the main door should be open only for the entrance of visitors of the family. Houses where the front door is left open are are vulnerable to free flow of negative energies especially when it faces south or west. This is applicable to offices as well. The only exception to this rule is commercial shops because of the constant exchange of energy that takes place. A customer walks in to purchase some merchandise and walks out after paying for it. Such spontaneous exchange of energy is not possible at home or in any office. Hence, an open door would only ensure the free outflow of energy which would primarily be in the form of wealth or happiness. Secondly, the placement of the front door is of prime importance, for which a simple formula has been devised. If you divide the front of your house into nine equal segments, the fourth from the left is considered to be the most auspicious. The application of the above is seemingly difficult to follow in flats, hence, for them either a window in the fourth segment or hanging a mirror would serve the purpose. When you superimpose a swastika symbol on your house plan, you will notice the fourth segment coincides with an opening in the symbol as well.