Who makes the best fiberglass replacement windows?

Answer: INFINITY from Marvin Windows

We think it goes without saying that the best fiberglass window is Infinity from Marvin windows. Made from Ultrex fiberglass, are the best fiberglass windows on the market. 

These are the facts:  Infinity's Ultrex Fiberglass is eight times stronger than vinyl and three times stronger than composites. That’s as tough as steel. So when a house settles and time marches on, Infinity replacement windows stay true and resist sagging—proving that they’re truly the best fiberglass window on the market.

Research and Find the Best Replacement Windows For Your Home. 

Learn which materials, types, and features are most important to consider.