The type of aluminium best for windows is thermally insulated profiles, typically using a polyamide thermal break, the latest generation insulator, creating a thermal bridge between the outside and inside profiles. Together with the double or triple-glazed glass in your aluminium frame, the thermally insulated aluminium profiles create an energy-efficient window. Another benefit of thermally insulated profiles using polyamide is you can easily have windows with a different colour frame inside and out.