Before we dive into the world of aluminum and steel windows and doors, let’s talk about science. Way, way back in grade school, you probably learned about the various conductive qualities of different materials. Materials like foam, fiberglass, wood, and plastic are excellent insulators – meaning that heat and cold don’t transfer through them quickly. That’s why oven mitts, wooden spoons, and foam insulation are so popular. Metal, on the other hand, is an excellent conductor – both heat and cold transfer through, around, and throughout metals like aluminum and steel very quickly.
In the world of windows, insulators vs. conductors are very important to understand. That’s why in a U-Value rating, it’s not just the insulation value of the glass that is measured. The entire performance of the window, frame and all, are measured by how much heat or cold is lost or gained through the total opening.
All that being said, aluminum and steel are still very common window and door materials, especially in commercial applications. Window manufacturers have designed these products to be “thermally broken” so they can perform at their best without suffering from major efficiency concerns.