In 1937, Adolf Kassl and Johanna Landwehr began a partnership in weather-stripping steel casement windows and developing a new storm window. Ten years later, Mr. Kassl forms the Karey Products Corporation moves to Mineola, New York and expands the product line to include storm windows, jalousie windows and "Williamsburg Series" combination doors. By 1960, with his two sons Robert and Ronald, Karey products is moved to a new 20,000 square foot state of the art manufacturing facility in Plainview, New York. The "Estate" Series storm window is now being mass produced.

With the replacement window at its early stages, The Kassl family develops the world's first "Tilt Sash Double Hung Window" in 1968, while expanding the Long Island plant an additional 20,000 square feet. By the mid 1970's a Non-Thermal line of "Coastal Windows and Shutters" is introduced and a partnership with TreeCon Limited is formed and the Bermuda market is opened.

As production of these lines continues, a heavy commercial double hung is developed and in 1984, The Kassl Window Company is formed. Shortly thereafter, the "Series 5000 VR" (Vandal Resistant) is introduced focusing on the school replacement market.

In 1995, having merged the Karey Products Corporation and The Kassl Window Company to form the Karey Kassl Corporation, a third generation Gary and Ronald Jr. ensure the Kassl "Standard of Excellence" will continue for years to come.