Duo-Corp. was established June 1977 in North Lima, Ohio. The first and only product manufactured, at that time, was an aluminum basement hopper window. This original basement window was manufactured in a 5,200 square foot building by a production/office staff of four (4) people. Over the course of almost 4 decades, the business has expanded into a 70,000 square foot facility manufacturing several basement, utility and egress window products with single shift production capabilities of 1,500 units per day.

Since its inception, Duo-Corp. has concentrated directly on the basement window market, and has engineered, developed, and manufactured products only for that segment of the window industry. By focusing on this highly specialized portion of the window industry, Duo-Corp. has developed, produced, and offered “true” quality basement windows at extremely competitive prices.

In 1984, the first vinyl basement window available to the window industry was produced – “The Aristoclass”. Tested by time and usage, “The Aristoclass” continues to be the premier vinyl basement hopper window sold in the United States window market.

In 1991, Duo-Corp. designed, manufactured, and marketed “The Patriot” and “The Competitor” vinyl basement hopper windows which have become two of the most recognized and used commodity basement windows in the industry.

During the early spring of 1998, Duo-Corp. introduced its double slider basement window complete with “Low E” high performance glass and full screen. This product was at its inception, and is today, unmatched for features and competitive pricing.

1998 also saw the introduction of our Double Sliding Utility Window, which is available in either Double Strength Tempered Glass or Insulated Glass. The Utility Windows include an integral full one-inch j-channel siding return and pre-punched nailing fin, features that are perfect for pole barn or utility building packages.

In January 2006 we introduced our Place-N-Pour Poured Wall Hopper, Slider and Egress Window System. This system is simple to use and is designed for use in any poured wall form system on the market. Our PNP System has become the predominant window used on the east coast.

Finally, January 2012 brought the introduction of our Renaissance Vinyl Barn Sash and our PNP Thermal Foundation Vent. The Barn Sash compliments our very successful line of utility sliders for the agricultural, farm and utility market while the PNP Thermal Foundation Vent rounds out our poured foundation products family.

It is said that “Imitation is the most sincere form of flattery”, this being the case, competitors have tried to manufacture and market windows that “look” like Duo-Corp. ’s. Every vinyl extrusion and piece of hardware used in our products is specifically designed for our applications. This is what Duo-Corp. has understood and perfected for 30+ years.