Our Fiberglass is Stronger than the Competition.

Pella® Fiberglass

Won’t Bend or Break as much as the
competition in a bend test and tensile strength test.


Fiberglass is STRONG. We Made it the STRONGEST Material for Windows.

We routinely test beyond requirements to ensure quality windows and doors that are built to last a lifetime of everyday use. But we wanted to show exactly how strong our fiberglass is to help you find the best fiberglass windows and patio doors for your project. With relentless strength and long-lasting durability, Pella’s proprietary fiberglass helps ensure less maintenance with fewer callbacks.