According to Varaha Puran, The temple doors must not be opened before blowing the left-handed shankh. When the shankh is blown The holy sound of om is emitted that helps us in attaining transcendence and removing the presence of any negative energy and evil spirits in the surrounding area.
A shankh, as the home of the goddess Lakshmi, can bestow peace, wealth, and fame.
Before we begin our prayers, its blowing can attract Lord Vishnu's energy to us.
Shankh has a sattva-dominant frequency, which reduces the intensity of evil forces.