Vastu shastra is understood and practiced in a very simplistic manner now-a-days. People just go by thumb rules and often miss the essence and subtle nuances, which link it in a holistic manner to other arsha vidya such as Jyotish, yoga and ayurveda.
For example, suppose someone has kitchen in southwest corner of the house. Based on thumb rules, this is very bad. In fact, I know several cases where people developed health problems after moving to such houses. However, only a subtle understanding of how this works will explain corner cases and exceptions better.
Southwest direction is owned by demon Nirriti (literally, “not proper/straight-forward”). The vibrations of Nirriti released in this corner of the house will have to be absorbed by the activities in that area (i.e. cooking food) and that can afflict the food with undesirable vibrations.
However, note that Nirriti also stands for bending rules, breaking barriers and unconventional things. Suppose someone does weird experiments and cooks unconventional food items. Then Nirriti’s vibrations will find expression in that spirit and will not afflict the food.
Similarly, suppose a child’s bed room is in southeast. If the child not only sleeps there but studies there, the vibrations of Agni can help one transform the reading and thinking one does into an understanding of the subject. If the child studies in a different room and only sleeps there, the fire may instead disturb the sleep.
Instead of learning thumb rules from a book, what one needs to understand how various energies and vibrations emanate from different parts of the house and land and balance one’s lifestyle and activities with those vibrations. Arsha vidya is never meant to be a set of blind thumb rules, but meant to provide a framework for intelligently harmonizing one’s life with the forces of nature - both physical and subtle.
Though there are many books that give thumb rules, which may or may not always work, the only book that impressed me for its holistic and thoughtful approach is “Vastu: Breathing Life into Space” by Dr Robert Svoboda. Dr Svoboda is one of the wisest scholars I have read and had the privilege of interacting with and his book is a bold first step into holistic and nuanced understanding of Vastu shastra.
May the spirit of rishis be re-kindled on earth and may there be a renaissance in Arsha Vidya!