Our History

Our Legacy

80 Years of Service

Every company has a story—and ours is rooted in hard work, vision, and a commitment to serving the mechanical industry. From a small, family-run operation to one of the Midwest’s largest independent suppliers, NSC has grown and thrived by staying true to our core values: reliability, partnership, and innovation.

Our Journey Through the Years

  • 1938

    NSC is Founded

    National Sales Company (NSC) is founded at its 1st location on West Pine

  • 1946

    Nabbefeld Heating & Cooling

    The Nabbefeld brothers founded Nabbefeld Heating and Cooling.

  • 1960

    Move to Tower Grove

    NSC headquarters is moved to Tower Grove location.

  • 1972

    St. Charles Location

    NSC establishes its St. Charles location.

  • 1980

    Moving on up

    NSC headquarters moves for the 2nd time to Duncan Avenue in St. Louis’ Central West area.

  • 1981

    First Acquisition

    NSC acquires Independent Plumbing.

  • 1982

    Move to O’Fallon

    The St. Charles location is moved to O’Fallon, Missouri.

  • 1984

    New Generation

    Mike and Nancy Jersa purchase NSC from John and Joe Nabbefeld (Nancy’s father and Uncle)

  • 2007

    The Family Business

    Lenny and Susanne Knese take over leadership from Mike and Nancy Jersa (Susanne’s Father and Mother).

  • 2012

    Consolidation

    NSC’s Duncan Avenue headquarters and the O’Fallon location are consolidated into one main location on Delmar Boulevard in downtown St. Louis.

The Legacy Continues

From day one, NSC has stood for reliability, service, and a commitment to our customers’ success. As we move into the future, we remain dedicated to building on that legacy—continuing to serve the mechanical and HVAC industries with the same passion, integrity, and innovation that has guided us for more than 80 years.