Renchérir belong to the 2
nd group. Renchérir is a common french verb.
Renchérir is conjugated the same way that verbs that end in :
-ir
Renchérir is conjugated with
auxiliary avoir.
Renchérir verb is direct transitive, intransitive.
Renchérir verb is a direct transitive verb, so ive voice can be used.