PVC or aluminium windows – OknoPlus explains

Plastic and aluminium windows have been compared for years. Customers have considered the old ‘pros and cons’ for years, though they have little to do with reality these days. At OknoPlus, we argue that modern technologies and the latest solutions offered by window manufacturers have effectively eliminated the ‘cons’ of the past.

Today, PVC windows no longer have to be a standard size, while metal windows are now energy efficient. Properly installed plastic frames no longer change colour over time, while aluminium options are readily available and are no longer just for big office buildings. Even more important for the customer – there is no longer a price gap between aluminium and PVC windows.

Dimensions – PVC small and large, aluminium… even larger

There is a misconception that plastic windows only come in standard sizes, and that they aren’t available in the large formats that are so popular today (for example, 1465 mm x 1435 mm). That’s not entirely true. PVC is no longer limited to the typical windows and balcony doors that – until recently – were so commonly used in residential developments. Today, plastic windows are adapted to suit the much larger dimensions characteristic of contemporary single-family houses, for example, with special frame reinforcements and mechanisms that allow them to handle heavy sashes. The PVC HST Swiss Form lift and slide structure, which reaches impressive dimensions of 6 by 2.5 metres, is a good example of this.

However, if you want even larger windows – as are so common in single-family houses nowadays (the average detached house may have as much as 30 square metres of glass) – you should go for aluminium frames. It’s aluminium structures that create those fashionable ‘walls of glass’ that blend the interior of the house with its surroundings. They are usually comprised of both fixed and sliding or swinging panels and can be more than 10 metres wide and several metres tall. Modern façades are made of aluminium and glass. Both metal frames – which are exceptionally strong – and plastic frames are used to create these extra-large window structures, including in unusual shapes. Among the recommended solutions is the Genesis system, which allows architects to ‘play’ with shapes and design even the most sophisticated windows.

Style – PVC isn’t just classic, and aluminium isn’t just avant-garde

We assume that plastic windows – which, by the way, can be styled quite freely in terms of colour and finish – are the better choice for traditional houses. And indeed – they can perfectly imitate the appearance of classic wooden windows. However, we would point out that these windows also look great in more modern houses, such as those based on Scandinavian designs.  The SwissForm Art line is a universal option recommended for both traditional and avant-garde architectural projects.

At the other extreme are aluminium windows, which are usually chosen only for modern houses. Indeed, their slim frames and dark grey colour (currently the most popular) certainly enhance the character and emphasise the design of modern, minimalist buildings. However, that doesn’t mean that aluminium windows can’t be used elsewhere. Metal frames, while retaining the advantages of metal, don’t need to look like metal at all. They are available in a range of woodgrain, matte, and glossy finishes, and can be designed with different interior and exterior colour schemes, which allows you to use different styles in different rooms while maintaining a consistent exterior appearance. Star aluminium windows from OknoPlus are particularly versatile in this context.

Durability – both plastic and metal are built to last

Today’s PVC windows are a far cry from the plastic windows of years ago, which warped quickly and yellowed from the sun. Modern designs don’t deform or scratch easily and don’t change colour. If you’re not convinced, just choose Morlite acrylcolor windows, which are built using acrylic glass – the most durable plastic material in the world. The finishing process makes the frames silky smooth and resistant to damage, dirt, and temperature.

Being made of metal, aluminium windows are naturally strong; therefore, the frames do not deform and can withstand the weight of very large panes of glass. They are also scratch-resistant, weatherproof, and anodised or powder coated, which fully protects them against rust and corrosion.  Importantly, aluminium windows – such as the Superial line from OknoPlus – are virtually maintenance-free.

Energy efficiency – both plastic and aluminium are good options

Used in passive houses and generally associated with energy efficiency, PVC windows do usually have excellent thermal insulation parameters. For example, our SwissForm Activ windows (a 6-chamber PVC profile with triple-glazing) can boast a heat transfer coefficient of U = 0.7 W/m2K.

However, aluminium windows are not necessarily inferior to plastics in this respect. Even if the metal frame itself has slightly inferior specifications, you can make up for it with the right insulative glazing, so the heat transfer coefficient for the whole structure can be just as good as a PVC window. Our Reveal windows, for example, offer a heat transfer coefficient as low as 0.68 W/m2K, which means they are energy efficient and an excellent choice for passive houses.

Costs – a smaller and smaller price difference between PVC and aluminium windows

Until recently, customers most often chose plastic windows for economic reasons – they were much cheaper than aluminium windows, which were always considered a luxury product. That was until OknoPlus started a revolution in aluminium window pricing – this year, we introduced a premium class aluminium window which is currently available for up to 40% less than comparable products from other recognised manufacturers


So… plastic or aluminium? The choice used to be more obvious, as it was easier to find the downsides of each solution. Today, both PVC and aluminium windows are so advanced, modern, functional and available that it is much harder to decide. To make the best possible choice, it’s worth contacting an OknoPlus advisor, who will help you select the ideal solutions, taking into account the architectural design, location, and style, as well as the family members’ individual needs and habits, and who will help you avoid potentially costly mistakes.