The system includes a plurality of mullion retrofit adaptors, each having a rear side configured and disposed to fit over the front side of at least some mullion of the existing supporting framework. It also includes a plurality of new mullions, each having a rear side configured and disposed to fit over at least some of the retrofit adaptors. A method for refurbishing an existing curtain wall attached to a base structure is also presented. This proposed concept can significantly reduce the time and costs for refurbishing an existing curtain wall.