Aluminium is a superb material that looks stylish when it is used to frame windows and doors. Indeed, it has been the first choice for many designers to create window frames since the early part of the twentieth century due to its architecturally pleasing visual properties. In addition, aluminium is a tough material that is able to withstand the elements robustly for many years after it has been fitted. Despite these great advantages, aluminium has a drawback: it conducts heat in a very effective manner.

Because aluminium is an efficient conductor of heat energy, designers need to take into consideration two factors. Firstly, in winter even double-glazed windows with an aluminium frame will transfer too much heat to the outside to make them acceptable to modern thermal loss guidelines. Secondly, under the baking Australian sun in summer, they will transmit heat into a building, much like a radiator, thereby driving up the energy costs associated with air conditioning systems. To overcome these problems, manufacturers of high-quality aluminium windows fit insulation bars into their frames.

What Are Insulation Bars?

When an aluminium window frame is constructed, each section will typically be made up of two profiles, one for the inside and one for the outside. If these profiles touch one another, then the undesired thermal transfer properties described above will occur. Nowadays, manufacturers stop them from touching one another by carefully fitting an insulation bar into the frame's profile so that a thermal break is created. Modern manufacturing methods rely on such inserts being rolled into place by machine rather than being manually fitted. Not only does this minimise heat loss during winter, but it helps to prevent overheating in summer, as well.

What Are Insulation Bars Made From?

A number of materials are chosen for creating thermal break insulation bars. Most are highly engineered thermoplastics. Types of nylon, otherwise known as polyamide, are a typical choice because they are durable and have great insulating properties. They must be inserted with great care into the aluminium profiles, however, or they won't function properly. Sometimes, window makers will select other types of plastic because they offer greater performance when they have been exposed to other processes, such as powder coating, which is a common finishing option for aluminium windows. Materials like acrylonitrile butadiene styrene and a blend of polyphenylene ether resin and polystyrene are also used extensively in window and door frames.