Obviously windows are made of glass; or rather, glass and, perhaps, a few other composite textiles. In this case, though, we are talking about base materials for NeuFenster window styles; in essence, the frame. Most window styles are available in a variety of materials and each material, of course, has its own set of advantages and disadvantages.
As you probably could deduce, windows have traditionally made out of wood. Of course, we still see wooden windows these days so their classic benefits, apparently, never go out of style. Indeed, wood windows offer quite a bit of versatility. Older wooden windows, though, might be draft but to solve that you can just install some weather stripping. Or you could install hardwood instead and that would just require oil seals for weather protection.
Another excellent benefit to wooden windows is the option to paint them. You can paint hardwood windows any color you want or just stain them for a natural finish. If you use softwood, though, you will need to apply stain or paint regularly to ensure proper maintenance.
Vinyl windows—often double-glazed—offer, perhaps the best heat and sound insulation. As a matter of fact, when people renovate an old house, they often choose to replace the older windows with more energy-efficient vinyl windows. But while comfort is obviously an excellent reason to choose vinyl windows, you might also appreciate that you can order them in a variety of finishes (including white and wood grain); and they do not require much maintenance at all.
Many homes today are outfitted with aluminum windows. This style is preferred with you require maximum light exposure. Aluminum windows are strong enough to support large glass panes, even in the thinnest of frames. But you have to keep in mind that aluminum is a metal and, therefore, conducts heat; it is also prone to condensation.
You can double-glaze aluminum windows if you want to reduce heat loss. In fact, some city codes require this. Also keep in mind that aluminum can be vulnerable to rusting, but modern versions are made with special coatings that help to minimize this.
While wood, vinyl, and aluminum are the most common materials used in making windows, you can find windows consisting of other materials too. Composites, actually, are also very popular: aluminum with a wood core, steel casements with wooden frames, etc.