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.  Two years ago included the MosaiK Festival concert "African Stories" with guest director Scott Leithead, singing John Rutter's Gloria with the Milford Brass, and a lively performance of Carmina Burana, with 2 pianos and lots of percussion, as well as a performance with the Finnish vocal sensation Rajaton, and even singing for Kenny Rogers at the National Art Centre..  Previous years have included a Christmas concert with vocal jazz ensemble "Quintessence", 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. Last year saw the Men's Chorus performing Brahms "Alto Rhapsody" with Julie Nesrallah, and the Ottawa Chamber Orchestra, and this year the Ladies Chorus will join the orchestra for a performance  of Holst's "The Planets" They will ended the season in 2014 with a concert with the Governor General Foot Guard Band. This April the choir is pleased to perform with both the Ottawa Chamber Orchestra on April 18th (Brahms) and the Divertimento Orchestra a week later with a celebration of Sibelius, including Finlandia.