You can mix and match the fabrication of windows. This is known as a  Hybrid Window. For example, a casement window is made from polyvinyl chloride (PVC), is a very versatile plastic with good insulating value, high impact resistance, and good resistance to abrasion. Because its color runs all the way through the material, there is no finish coat that can be damaged or deteriorate over time.

The outside is made from aluminum and is extremely resistant. This is a popular hybrid window combination, offering the best of both worlds.