Every human body is encircled by three types of Energies which form an Energy triangle around it. These are - The Earth Energies, The Directional Energies, The Cosmic Energies
Vaastu means building a Positive Energy into the house or any other building.
It is a great combination of Science, Art, Astronomy and Astrology. Also we can say, it is an ancient Indian Vedic Building Science which puts down parameters on the construction of buildings, so that they are in harmony with the natural environment by managing the flow of cosmic energy (that is 'prana' ) through and around them, which in turn supports the well-being, peace and prosperity of the inhabitants.
Vaastu Shastra assists us to make our lives better and will secure from things going wrong.