In the USA and the UK uPVC or rigid vinyl windows are far more popular than aluminum windows. Whereas, in Japan and other Asian countries the reverse is true: most windows have aluminum frames. So what is the difference between these two types of frame?
Aluminum frames are cheap and easy to install. In Japan a house is normally built with a wooden frame and lightweight walls. Windows are fitted quickly. The house is not expected to last for much more than 60 years. After that time it is demolished and a new house is built on the same plot of land. Aluminum frames suit this style of construction because they are long lasting, light and cheap. Aluminum frames are also weather resistant. Aluminum doesn't rust; instead it just takes on a dull tone from oxidization.
Aluminum windows are superior to uPVC windows in terms of longevity - they last much longer than uPVC, which normally has a life expectancy of about 25 years. However, there are a number of ways in which uPVC or rigid vinyl windows are better.
The first is thermal resistance. Japanese houses are very cold in the winter and too hot in the summer. This is partly because aluminum windows do not provide a good thermal barrier: in the winter they don't keep the heat in the house, and in the summer they don't stop the heat from outside entering the house. Whereas, uPVC windows, especially with double glazing, are good insulators. They prevent heat or cold escaping from a room and stop the heat or cold from outside entering a room. This is called thermal resistance. uPVC's high thermal resistance helps save money on heating and cooling costs. Aluminum's poor thermal resistance makes heating and cooling a house more expensive.
Another important difference between aluminum frame windows and uPVC windows is strength and security. Aluminum is a lightweight and malleable metal. It is very easy to dent and bend aluminum frames. This means they are an easy option for burglars. In contrast, uPVC is stiff, hard and rigid. uPVC is a tough material that is difficult to break or bend. uPVC frames combined with double glazing present a much more formidable challenge to a would-be burglar than aluminum window frames.
The final difference between the two window types is disposal. It is easy to recycle aluminum. For years now many countries have been recycling aluminum cans and covering the costs by selling the recycled metal. On the other hand, it is very difficult to recycle uPVC. uPVC is a plastic that contains PVC which is made from petroleum. When burnt PVC gives off dioxins that are health hazards to people. Sadly a lot of uPVC and other PVC products end up in land fills at their end of their lives. These land fill sites frequently are the scenes of fires. Thus, if uPVC windows are not safely disposed of they are a danger to human health and a pollutant.