How to choose plastic windows: structures and profiles of PVC windows

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From year to year, the opinion is heard that the system of profiles for PVC windows has exhausted its potential and nothing new can be invented. However, in the context of energy-saving technologies, many new products and improvements have appeared. Today we’ll figure out which of them are really useful, and which are just marketing tricks..

How to choose plastic windows: structures and profiles of PVC windows

Features of the device of profile systems

It is not for nothing that a plastic window profile has such a complex sectional shape. Numerous partitions play the role of both strengthening the strength and preventing the outflow of heat by lengthening the cold bridges.

There are several leading trends that the developers of PVC profiles are adopting. The main ones are the improvement of the profile extrusion technology and the introduction of new, more durable materials. Design innovations in terms of the configuration of walls and partitions are more and more rare, the main solutions have been found long ago and have proven themselves perfectly in real use..

VEKA window profile production

Nevertheless, modifications to the profile shape are periodically carried out, mainly the issue of increasing the number of chambers is being addressed, additional sealing contours are also provided, work is underway on the soundproofing ability of the frames and more efficient drainage of rainwater and condensate.

It should be noted right away that manufacturers resort to all kinds of tricks to improve the heat-saving characteristics of a profile less and less. It is considered that 7 and 8 chambers in a profile with an assembly width of more than 80 mm is a practical maximum. The explanation is simple: in terms of area, the glazing of a window takes up to twenty times more than the frame and imposts, at the same time, sound and heat penetrate through it many times better. The benefit from improving the profile is tangible only with the outstanding resistance of glass units to heat transfer, while the main work is being done to increase the practicality of the windows and their adaptability to new types of fittings.

PVC profile

In an effort to save money, many customers choose windows with a lot of “blind”, non-opening parts. The rejection of some of the sashes really allows you to reduce the cost of the structure, but makes such a window extremely inconvenient to use, and sometimes just dangerous. Even if you open the window once or twice a year to wash it (and in our cities you have to do this more often) – do not save on your own comfort and safety and do not turn your apartment into something like a greenhouse or an aquarium – avoid “blind” parts and plan sash dimensions rationally.

Sergey Elnikov, Head of Marketing at VEKA Rus

Plastic windows VEKA

Material and manufacturing technology

It would not be entirely correct to consider the lead-free technology for the production of PVC profiles as a novelty; today they are not used only in handicraft production. The main milestone in modern window production is considered the introduction of plastic recycling, which makes it possible to include in the composition of recyclable materials without compromising strength and appearance. At the moment, this technology is being mastered by most of the leading manufacturers, it makes the profile material even more environmentally friendly and recyclable..

Production of PVC window profiles

Another innovation is slow extrusion methods. For example, REHAU has adopted this technology in the Synego and Brilliant-Design series of window profiles. This method of production provides excellent accuracy and geometry consistency, as well as high profile strength due to the reduction of polymerization defects..

One of the modern breakthroughs is the elimination of air-filled chambers. The injection of polyurethane foam inside the profile has the best effect on both heat-saving properties and strength: the foam has almost dead adhesion to plastic partitions and prevents them from deformation. The GmbH Energeto 8000 foam series from Aluplast is a typical example of such a solution, a similar approach is used by REHAU in the Geneo PHZ product and Veka in the Alphaline profile series. Foam-filled profiles are considered to be the best solution for passive and energy efficient homes today. It should be noted that not all chambers are filled with polyurethane, the most filled can be called KBE 88 passiv profiles, where out of eight chambers foam is present in four.

Profile system Veka Alphaline Profile system Veka Alphaline: 1 – grooves for installing the support profile; 2 – profile width 90 mm, outer wall thickness 3 mm; 3 – closed steel reinforcement; 4 – filling with a heat insulator; 5 – three additional contours; 6 – multilevel camera system; 7 – sash reinforcement; 8 – glazing bead; 9 – glass unit seals; 10 – energy-saving glass unit 44 mm thick

Profile manufacturers are increasingly using composite materials. This includes PVC plastic containing fiber – this is a kind of attempt to abandon the steel reinforcement of profiles. This solution fits well with the concept of building passive houses: REHAU has developed Rau-Fipro material with fiberglass inclusion in plastic, and the already mentioned Energeto 8000 series uses reinforced insert partitions without a rigid connection to the profile, which prevents heat transfer. It is too early to talk about the final abandonment of reinforcement, but without significant wind loads and vertical moment such windows can be successfully used today..

Sealing contours

The insulating capacity of opening sashes is traditionally provided by two (in type AD designs) and three (in type MD) rebate sealing circuits. In this direction, two innovative trends can be traced:

  1. Placement of seals on the opening sash to prevent damage when the window is open.
  2. Application of a special groove to the bottom frame profile for the installation of a valve-shaped seal, as in the profiles of the IN-M5 series from Trocal.

VEKA Softline profile

Also, the development of new materials does not stand still. REHAU has developed a new material for sealing contours – Rau-Pren. The distinguishing features are reduced pressing force, high plasticity at a wide temperature range and increased service life. At the moment, such gaskets are used in the Synego and Geneo profile series..

Fitting groove filler

To improve the insulating capacity, many manufacturers have added protruding grooves on the movable leaves to their profiles in order to form an additional sealing contour. This solution is used in the Veka Alphaline and IDEAL 8000 profiles from Aluplast. The purpose of the additional rebate is to eliminate the penetration of rain and condensation moisture into the hardware rebate, even when the sash is folded back.

Opening systems and fittings

Over the past 3-5 years, several new developments have been outlined in the field of locking fittings. The most active work has been and is being done to ensure burglary resistance. These are mushroom-shaped trunnions, and special landing grooves for glazing beads; it is also practiced to install retractable hooks and strike plates with double-sided locking. A very wide range of anti-burglar fittings is available from the manufacturers Siegenia, Roto and Maco.

Mushroom trunnion of plastic window

The range of hidden fittings is expanding. In the Siegenia-Aubi and Roto Designo series, you can find products for both tilt-and-turn three-mode windows, and for roof or sliding windows. The restrictions on the opening angle of the sash have been eliminated, the micro-ventilation function has been implemented while maintaining burglary resistance. The requirements for the safety of windows for children are also taken into account: the Roto Tilt First fittings differ in the switching of window modes: the sash can only be opened by turning the handle up and only with a key.

Roto Tilt First baby fittings

Manufacturers of profiles for PVC windows are not lagging behind: new hardware samples require certain conditions for installation. At the moment, it is considered the general norm to have a hardware rebate with a depth of 31 mm and a special shape of profiles that does not require milling for inserting stops, hinges, locks and hidden elements. In parallel, the performance characteristics of the fittings are expanded: the adjustment and switching modes are simplified, friction in the nodes is reduced, the pressure distribution and the operation of microlifts are improved.

Mullions, expanders and support profiles

The range of products for the production of windows cannot be called complete without additional products provided for installation in special conditions. For example, support profiles for systems with an installation depth of more than 50 mm are already produced not in one piece, but in stacked ones. This helps to bypass complex openings with an uneven protrusion of a quarter, as well as provide a more technologically advanced abutment of window sills and sills without compromising thermal insulation.

Base profile

Expanders of many famous brands are produced interchangeably with the same shape of the locks for a tight connection. At the same time, the width of the extensions may differ from the installation depth of the frame itself. This makes it possible to replace the base profile with a more powerful extension to match the existing class of loads, while the installation technique of the window sill and ebbs is almost the same as the standard.

Additional PVC profiles

For each new profile line, a corresponding cross-section of imposts is developed. The main trend is considered to be the displacement of the main chamber under the reinforcing element closer to the outer side with numerous partitions of “warm” chambers surrounding the glass unit. To facilitate the assembly of the structure, sagging in the places where the screws are screwed in can be provided, as well as a more complex shape of the partitions to strengthen the welded joints. In some cases, the fastening of imposts to the frames is carried out using steel plates.

Installation of plastic windows VEKA


One of the main innovations in the production of PVC windows are the methods of coextrusion, which allow applying a texture pattern to the front walls of the profile. This is an example of how to avoid profile lamination, the service life of which is 2-3 times lower than that of plastic. The same technological methods are used to form the so-called silky and ideally glossy snow-white surface of the profiles. In particular, a series of Synego profiles has a composite frame system structure: inside is recycled plastic, outside – fresh and clean snow-white PVC polymer of primary type.

Veka Alphaline 90

Composite profiles are not uncommon in the window market today. In the already mentioned Synego, it is possible to complete the window with replaceable overlays of various types. A similar approach is demonstrated in the PremiDoor 88 AluClip range of sliding glazing profiles from Trocal: the outer surfaces are made of aluminum, while the inside the profile is made of high quality PVC.

To ensure the preservation of the appearance and cleanliness of windows, manufacturers strive to optimize the shape of the glazing beads and protrusions adjacent to the glass unit. Salamander Design 3D profiles have rounded outer and inner edges that are virtually free from dust and dirt.

Design 3D Salamander Profile

Plastic windows do not have to be white at all. They can have different colors: both on one and on both sides, and these colors can be different. Not only the surface of the window profile, but the profile itself in the mass can also have an original color (for example, brown or caramel). Even more possibilities are opened up for designers by aluminum plates, which can be painted in any color scheme. Window seals can also be of various colors, for example, black, gray and caramel.

Sergey Elnikov, Head of Marketing at VEKA Rus

Colored windows VEKA

Other features

Design solutions can be very diverse. But do not forget that the window profile must correspond to the established classification by wall thickness. For example, the Salamander Produkte GmbH Streamline profiles have a wall thickness of 3 mm, which can certainly be called a record figure among other manufacturers. At the same time, the thermal conductivity of the windows is very low, mainly due to the well-thought-out scheme of division into chambers and the placement of sealing circuits. The main advantage of the high profile thickness is its good weldability, which reduces the risk of rejects when welding on insufficiently technological equipment.

PVC profile thickness

The basic principles of improving thermal efficiency are clearly visible when considering the InnoNova-M5 profiles from Trocal. The partitions in them are oblique X-shaped, due to which the outflow of heat occurs along the longest path. The structural strength of the profile is also excellent. Such techniques are not always obvious at the first acquaintance with a particular profile, but it is these features that determine the differences between different types of profiles..

VEKA profile


It is very important to understand that the achievements of the industry demonstrated at exhibitions may remain inaccessible to the domestic market for a long time. What is considered an innovation in Russian construction has been successfully used by Western manufacturers for more than one year..

VEKA windows

The explanation is simple: launching a new product on sale requires justifying the costs of marketing and advertising, and only a few developers are in the habit of adopting innovations of this kind. On the other hand, a quality product comes into the hands of the consumer, which has been tested by operation in European countries, where the requirements for such structures are much more stringent. Now, knowing the features of modern windows and their real benefits, you can easily navigate the profile systems and fittings offered by your supplier..

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