The term tretagni in Hindu rituals refers to the group of
three fires. They are Grahapatyagni, Dakshinagni and Ahavaniyagni. The three
fires must be kindled in the house of an agnihotrin. Tretagni is also known as
Srantagni.
Grahapatya fireplace is mostly circular in shape and on rare occasion, it is square shaped. It is set up on the western side.
Grahapatya fireplace is mostly circular in shape and on rare occasion, it is square shaped. It is set up on the western side.
Ahavaniya fireplace is always square shaped. It is set up on
the eastern side of Grahapatya.
Dakshinagni or Anuvaharyapacana fireplace is always in the shape
of a semicircular. It is always set up in the southern side.
Though the shapes are different, the area is always the same
for all the three.
The establishment of Tretagni is mentioned in the Vedic
texts.
The distance between the three sacred fireplaces varies from
scripture to scripture.
The Grahapatya fire is considered to be prana breath,
Ahavaniya apana breath and Dakshinagni is vyana breath.