Harmonia is one of the two host choirs for the MosaiK Choral Festival.  For several years Harmonia hosted a Black History Month concert, with intergenerational guest choirs and soloists, including the World Voices Choir (Brookfield High School), Cross Town Youth Chorus, Kathy Grant, Cathy Goddard and Vanessa London. Out of that annual project has come the MosaiK Choral Festival, now involving several local, but still intergenerational choirs.

Founded in 2003 by its current artistic director Kurt Ala-Kantti, the choir has carved out a niche in the Ottawa choral community.  While still maintaining a focus on Canadian and local composers the choir takes on an eclectic mix of repertoire each season.  Previous years have included an annual Christmas concert with the Ottawa Wind Ensemble, Handel's "Messiah", Faure's "Requiem" with the Divertimento Orchestra and 2 performances of Brahm's "A German Requiem", one here, and one in Carnegie Hall, directed by John Rutter. The choir returns to Carnegie after performing Mozart's Requiem here in Ottawa the choir will return to Carnegie Hall to perform it with MosaiK alumni director Laurier Fagnan in June.