How does Vinyl compare to Fiberglass as an insulator?
If you look at the test results for window framing materials, vinyl is a much better insulator than fiberglass. Traditional “pink” fiberglass, used to insulate the walls and attic of your home, insulates by trapping small air pockets it. However, the pultruded fiberglass used in window frames is so compacted that it cannot trap air and consequently, is not a very good insulator. As a matter of fact, fiberglass window frames transfer cold three to four times as much cold as an equivalent vinyl window frame.
