Window Frame Materials: What Window Manufacturers Often Don’t Tell You

When shopping for windows, the window salesperson typically places much emphasis on window glass. They love to talk about window glass because of magic words like argon, krypton, and R-values. Window glass allows them to pull gimmicks out of their bag, like having you place your hand on the other side of glass from a blow torch (“See, no heat!”).

But when it comes to window frame materials, they usually brush the topic aside.  Window frame materials, after all, aren’t very “sexy” topics.

Consider the fact that with some window sizes, the window frame comprises nearly a quarter of the total area.

So, why isn’t window frame material emphasized more often?

Here is a list of window frame materials and how well they block heat or cold, from worst to best:

1. Aluminum, no thermal insulation.
2. Aluminum, with insulation.
3. Wood clad in aluminum.
4. Wood or vinyl.
5. Insulated vinyl or insulated fiberglass.