Built to Last

Napco^® Premium replacement windows have been crafted to last for as long as you live in your home – we guarantee it. We offer a lifetime limited warranty on the entire window unit – and it’s transferable should you decide to sell your home. Plus our windows are backed by an exceptional seal failure warranty.

Fusion Welding

The Napco Premium 3500 replacement window features a fusion-welded frame and sash to create a superior barrier against wind and weather. Fusion welding literally bonds vinyl sections into a single piece for greater strength, more rigidity and superior thermal efficiency.

Heavy-Duty Weatherstripping

Air infiltration is a major cause of energy loss in your home. Our heavy-duty weatherstripping creates an effective barrier to air and water. In fact, our casement windows offer one of the lowest air infiltration rates in the industry.

Double-Strength Insulating Glass

Unlike most manufacturers, Napco utilizes double-strength annealed or tempered glass for all of our window units. This thicker glass provides increased strength and sound reduction.