Vastu is not a religion it's a science of setting the things correctly and balances the five elements that is Earth, fire, water, space, and air to have the maximum benefit out of life.
Vastu, the meaning of vastu is dwelling, which is the home for god and humans. Vastushastra is based on various energies that come from atmosphere like solar energy from sun, cosmic energy, lunar energy, thermal energy, magnetic energy, light energy, wind energy. These energies can be balanced to enhance peace, prosperity and success. If a house is made according to these principles, the inmates enjoy all the happiness in life. If it is against vastu principals, it will be a place for all sorts of problems, worries and no peace.