Technology and features Windows

Four equally important elements affect the thermal insulation of a window: the timber construction, the glazing unit, the seals and the way it is installed. Even the best glass will not deliver the expected result if the other parts of the window, or its joint with the wall, are weaker.

• Laminated timber The frame and sash construction made of laminated timber gives high dimensional stability throughout its service life. A well-designed timber profile affects the thermal insulation, the airtightness and the durability of the whole window.
• Sealed glazing units The glazing unit can be double or triple glazing. It is matched to the profile depth, the thermal requirements of the building, the size of the glazed area and the comfort expected in use. What matters is not only the Ug value of the glass itself, but also how it is joined to the frame: a warm edge spacer limits heat loss at the edge of the glazing unit and improves the Uw value of the whole window.
• Seals Seals are designed and selected for the specific window profile. They keep the joint between sash and frame tight, limit the passage of air and rainwater and help maintain a comfortable temperature inside the building. Their quality, correct seating and condition affect the day-to-day use of the window and its durability.
• A warm, airtight installation The Uw value describes the properties of the window itself. For its thermal insulation to be of use in the building, the joint between the outer frame and the wall matters just as much. A warm, airtight installation limits thermal bridges and uncontrolled air movement around the frame. The joint between the window and the wall should be properly insulated and protected against moisture, and the window itself fixed securely in the reveal.

When choosing windows, it is worth paying attention above all to the thermal transmittance Uw, expressed in W/(m²K). It is a value for the whole window, covering the glass, the frame and the joint between the glass and the frame. The lower the Uw value, the better the thermal insulation of the window and the smaller the heat loss.

Why Uw depends on size

Windows made in the same system can have different Uw values. This follows above all from their dimensions, from the ratio of the glazed area to the frame area and from the design solutions used.

A large window with a high proportion of glass can achieve a better Uw value than a small window from the same system. A modern triple glazing unit often has a lower Ug value than the Uf value of the frame.

The Uw value is affected by, among other things:

• the dimensions and shape of the window
• the proportion of glass area to frame area
• the type and thickness of the timber profile
• the type of glazing unit and the Ug value
• the use of a warm edge spacer
• mullions, transoms, glazing bars and other divisions
• non-standard constructions such as arches, raked heads, fixed lights and large glazed areas

The Uw value given by the manufacturer should always refer to a specific size and configuration. The value declared for a reference window need not be identical to the result for every window ordered for a particular building.

The requirements for the thermal insulation of windows are set out in the Regulation of the Minister of Infrastructure on the technical conditions to be met by buildings and their location. For new buildings and for the external elements of rooms heated to a temperature of at least 16°C, the following maximum values of thermal transmittance apply:

The glazing unit values for the three profile depths are compared on the timber windows page. See the profile comparison →

What do the RC classes mean?

The RC classes describe how far a window resists an attempted break-in in accordance with the PN-EN 1627 standard. They do not mean that a window cannot be forced. They state how long the complete assembly holds out against the tools laid down for the class in question.

The RC class applies to the whole window, not to a single component. It covers the construction of the outer frame and the sash, the glazing, the hardware, the handle, the locking points and the way the window is fixed into the wall.

RC2: certified resistance

RC2 is the most frequently chosen security class in public buildings as well as in detached houses, in ground-floor flats and for patio doors and windows that can be reached from a terrace, garden or balcony.

We hold a certificate confirming the burglary resistance of our joinery in class RC2. The certificate refers to one specific, tested window configuration. To keep class RC2, the components used must match the certified solution, including the appropriate construction, the hardware, glass of at least class P4A and the specified configuration of the locking mechanisms. In addition, the glazing beads in certified windows are permanently bonded in place or screwed down, so that the glass cannot be pushed out.

Installation is part of class RC2

The RC2 certificate does not cover the finished window alone. The burglary resistance must also be preserved once the joinery is set into the building. For that reason, the installation of burglary-resistant joinery should always be planned together with the choice of window and the construction of the wall.

An important rule in everyday use

Burglary-resistant features work only when the window is properly closed. A sash left in the tilt position, in the vented position or in micro-ventilation does not keep the declared RC resistance.

Magnetic contact

An opening sensor for the window, fitted during production and connected to the alarm panel. It reacts as soon as someone tries to get into the building, unlike motion detectors placed inside. The version integrated into the perimeter hardware also reacts to tampering with the hardware or the handle. An important part of keeping a whole house or building secure.

A good timber window is made long before the glazing and the fitting of the hardware. Its durability, its stability and its appearance years later are decided by the quality of the timber, the precision of the machining and the control of every stage of production.

From the timber section to the finished window we run a process in which the details matter. Every component has to add up to a coherent, durable and attractive construction.

Carefully selected timber

For our windows we use high-quality pine, larch, meranti and oak. Each species has its own character, colouring and properties, so we choose it to suit the design, the intended effect and the conditions of use.

The profiles are made from laminated timber sections, usually from three laminations. This construction increases the stability of the material and limits the natural movement of timber caused by changes in temperature and humidity.

Before machining begins we check the quality and the moisture content of the timber. This is an important stage, because material that is too wet or over-dried can lead to distortion during production or later, when the window is in use.

Precise machining of the profiles

From the selected timber sections we make the profiles for the frames and sashes. The components are machined, fitted and sanded to the precision required.

Making the outer profiles of the frames and sashes calls for particular accuracy. They are responsible for the look of the window, the correct working of the sash, the drainage of water and a tight joint between all the parts of the construction.

Four-coat protection for the timber

Before painting, the components are carefully sanded. We then apply the coating in a four-coat system that protects the timber and brings out its natural grain. The process comprises:

• impregnation, which protects the timber and prepares it for the following stages
• a colouring primer, which gives the colour and evens out the appearance of the surface
• an intermediate coat, which closes the pores of the timber and creates a uniform base
• a topcoat applied twice, protecting the surface against the weather and everyday use

We choose the paint system to suit the species of timber, the colour and the exposure the joinery is expected to face.

Assembly, glazing and inspection

At the final stage we put together the frames and sashes, fit the hardware and install the glazing units. As standard we use double or triple glazing, matched to the profile, the thermal requirements of the building and the expectations of the client.

The windows are fitted with hardware from the well-regarded German manufacturers G-U and Roto. These are responsible for the smooth operation of the sashes, for tightness and for safe use.

Timber is the oldest and most widely used material for making windows. Not only because it is a completely natural, environmentally friendly product that is pleasant to the touch, but above all because it offers excellent acoustic and thermal insulation and resistance to the weather.

The high quality of timber windows depends on properly selected and dried timber and on its density.

Many timber species can be used to make timber windows.

Our range includes products made of pine, larch, oak and meranti. Of course, the list is not exhaustive: if a client would like windows in another available species, we check its availability too.

Pine

Because of its price and availability, the most popular softwood used in timber windows and doors. It is regarded as one of the longest-living plant species on earth. The best properties come from trees 80 – 120 years old. With a density of around 450 – 550 kg/m³, it has good compressive and tensile strength.

Pine is relatively durable and strong, yet flexible and easy to work, and it insulates very well. Its high resin content makes it resistant to damage from moisture, but at extremely high temperatures the resin can bleed through the paint. The timber is light in colour and takes both opaque and translucent finishes well.

Larch

The best and most durable construction timber among softwoods, with a very attractive, regular grain. The best technical properties come from trees felled at 100 – 120 years of age. It is excellent for timber windows and doors. Larch is characterised by very high resistance to moisture – it does not suffer biological decay and does not deform as a result. Over time, larch becomes harder – a process known as “turning to stone”. Its density is over 550 kg/m³. Its high resin content means that at extremely high temperatures the resin can bleed through the paint. Larch is, however, quite rare and therefore relatively expensive.

Oak

It is the best construction material among native hardwoods, better even than pine and larch. Oak is counted among the noble species and is a symbol of dignity, strength and exceptional durability.

Only heartwood from the trunk should be used for windows, because the sapwood is easily damaged by insects. The best technical properties come from trees felled at around 180 years of age. It is a hard, heavy timber, resistant to water and abrasion. Its density of 650 – 750 kg/m³ gives it the best strength of all timber species found in the country.

It is worth mentioning that, thanks to its density, oak achieves much better sound insulation. Windows with such frames and suitably chosen glass will be both luxurious and soundproof. The high tannin content, formed naturally as the tree grows, increases its resistance to insects and decay (fungi, mould), but it is also a drawback: the tannins, with their strong, lasting sour smell, harden in water and darken over time as a result of chemical reactions between the tannins in the timber and iron compounds in the water, and because of the porous structure, which is difficult to protect effectively, micro-cracks may appear after some years.

The attractive grain and colour of oak windows have enjoyed lasting recognition and prestige around the world for centuries. Their high performance and attractive appearance make them very expensive.

Meranti

An exotic hardwood from Indonesia, Malaysia and the Philippines. Among exotic species, it is the one most often used by manufacturers. It comes in several varieties, of which white and red are the most popular. The density of meranti depends strongly on the species and ranges from 300 kg/m³ to 800 kg/m³. It is worth finding out the density of the timber, as it affects its properties.

Our company offers a variety with a density above 450 kg/m³. In general, the timber is highly resistant to moisture and therefore unlikely to crack. It is durable and strong. It achieves very good thermal and acoustic insulation. It has a distinctive grain, so it looks very striking with a transparent finish. An analysis of the main physical and mechanical properties shows that meranti is more weather-resistant than pine.

Meranti outperforms pine technically in areas of use such as shrinkage and swelling by 39%, in static bending strength by 41% and in hardness by almost 40%. The resistance of exotic species to shrinkage and swelling comes from their anatomical structure. They are heartwood species whose timber has low water permeability. Its reddish-brown colour gives products elegance and interiors a warm feel.

Meranti windows will please anyone looking for exotic beauty combined with high-quality, durable products.

See also:

Three profile depths

We fit hardware from the renowned German brands G-U and Roto. It is responsible for the light action of the sash, a tight close and day-to-day comfort in using the window.

• Turn and tilt A single handle opens, tilts and closes the sash.
• Micro-ventilation as standard Opening the sash by a fraction supports air exchange without tilting the window fully.
• Multi-point locking Even compression of the sash against the frame improves the seal and the stability of the closure.
• Mishandling device It helps to prevent the window from being operated incorrectly.
• Sash lifter It makes closing easier and supports the correct position of the sash in the frame.
• Central locking bolt Used in double-sash windows. It provides the right compression of the passive sash and convenient operation.
• Corrosion protection For joinery installed within 30 km of the coastline, special corrosion-resistant hardware has to be used.
• Additional solutions Lockable window handles, opening restrictors, magnetic contacts for the alarm, smart home components, RC2 solutions, fanlight openers, ventilation functions.

Security and configuration

We select the hardware to suit the size, weight, opening method and intended use of each window. For joinery with RC2 burglary resistance, the components used, including the hardware, the glass, the handle and the method of installation, must match the configuration covered by the certificate.

As standard we use glazing units matched to the profile depth, the thermal requirements of the building and the character of the project.

A double glazing unit consists of two panes of glass and one cavity between them. A triple glazing unit, also called a three-pane unit, consists of three panes of glass and two cavities filled with argon. SWISSPACER warm edge spacer bars reduce heat loss where the glass meets the frame.

What does a warm edge spacer do?

The SWISSPACER warm edge spacer bar reduces the thermal bridge where the glass meets the frame. It helps to raise the temperature of the inner edge of the glass, lowers the risk of condensation and supports better insulation across the whole window.

Glazing matched to the project

Besides its thermal performance, the glazing unit can be matched to the individual needs of the project. Depending on the design, we offer glazing that is:

• safety and burglary-resistant
• acoustic
• solar control
• ornamental, obscure or decorative
• of enhanced thermal insulation

When choosing the glazing unit we consider not only the Ug value, but also the requirements for security, acoustics, sunlight, privacy and the character of the architecture.

As standard, our windows are fitted with the SWISSPACER Ultimate warm edge spacer. It sits at the edge of the glazing unit, between the panes of glass.

SWISSPACER Ultimate limits the thermal bridge where the glass meets the frame. This improves the thermal insulation of the whole window, raises the temperature of the inner edge of the glass and helps reduce the risk of condensation. It is a small component, barely visible at first glance, that makes a real difference to comfort in use, to the durability of the joinery and to the final Uw value of the window.

Why the spacer material matters

As standard we fit our windows with HOPPE Secustik window handles, available in four colour options.

Secustik technology includes an integrated blocking mechanism that makes it harder to move the window hardware from the outside. The handle turns freely in normal use from inside, while during an attempt to tamper with the hardware from outside the mechanism blocks it from being turned.

The distinctive, precise click heard as the handle is turned confirms that the Secustik mechanism is working. The sound is produced when the spring-loaded security pins snap into the corresponding positions of the mechanism.

Colour options

G-U concealed hardware is a solution for architecture in which clean form and a well-considered detail matter. The hinges and the load-bearing parts are hidden between the frame and the sash, so they remain invisible once the window is closed.

With no visible hinges, the natural beauty of the timber comes to the fore, the slender line of the window is emphasised and there is no need for hinge covers colour-matched to the joinery.

This section describes the components that make up hardware with increased burglary resistance. What the RC classes themselves are, how long a window holds out and what the certificate covers is described in Burglary resistance classes.

What burglary-resistant hardware consists of

• steel security keeps in the corners
• stainless steel mushroom cams on the locking bars
• an anti-drill plate covering the fixing
• a lockable HOPPE Secustik window handle, which prevents the hardware from being moved
• burglary-resistant glass of at least class P4A in class RC2

Magnetic contact

A magnetic contact is an opening sensor for the window, fitted during production and connected to the alarm panel. It works on the principle of a magnet and a tube with sealed-in contacts. It reacts as soon as someone tries to get into the building, unlike motion detectors placed inside. The version integrated into the perimeter hardware also reacts to tampering with the hardware or the handle.

The glass in a window affects more than just the amount of light. It also determines privacy, security, sound insulation, solar protection and the appearance of the joinery as a whole. We match the glazing units to the architecture of the building, the location of the project and the individual expectations of the people who will use it.

Decorative and ornamental glass

Decorative glass gives windows and doors an individual character. We use ornamental, obscure, tinted and stained glass, among others.

Ornamental glass diffuses the view while still letting light into the room. It works particularly well in entrance doors, internal doors, bathrooms, studies and windows facing neighbouring buildings. The pattern is formed by rolling molten glass between two cylinders, one of which carries an engraved design; we make ornamental glass clear, body-tinted or wired.

We make stained glass as a decorative element matched to the character of the house, the architectural detail and the interior design. It can be a subtle addition to the joinery or a bold, individual accent. More about the stained glass we use in our joinery: witraz.pl.

Solar control glass

With large glazed areas, conservatories and windows facing south and west, it is worth using solar control or reflective glass.

A special coating limits the amount of solar energy passing into the room, which helps to reduce overheating in summer. At the same time the glass can give the glazing a slightly reflective or tinted appearance; reflective glass is sometimes body-tinted bronze, grey, green or blue.

We select the performance of the solar control glass individually. We take into account the size of the glazed area, the orientation, the shading, the function of the rooms and the level of light transmission required.

Safety and burglary-resistant glass

Laminated glass consists of two or more sheets of glass bonded with a PVB interlayer. When it breaks, the fragments stay bonded to the interlayer, which limits the risk of injury and reduces the risk of an opening being made in the glazing.

We select burglary-resistant glass according to the classes of PN-EN 356. Depending on its build-up, it can provide resistance from class P1A to P8B. Windows in burglary resistance class RC2 require glass of at least class P4A, and RC3 at least P5A.

Swipe sideways to see the whole table →

Acoustic glass

A standard glazing unit provides basic acoustic protection: a build-up of 4 mm float, a 16 mm cavity with argon and 4 mm low-emissivity float gives sound insulation of 32 dB. If the building stands beside a busy road, a railway line, an airport, an industrial plant or another source of noise, it is worth using glass with enhanced sound insulation.

Acoustic units use carefully chosen pane thicknesses, an asymmetric build-up and laminated glass with a special acoustic PVB interlayer. The solutions available can reach verified sound insulation values of up to about 43 dB, depending on the whole glazing configuration.

The final result depends on the whole window, on its size, its construction, its air tightness, the way it is installed and the conditions on the site.

At the client’s request, Wiktorczyk windows can be fitted with any window handles available on the European market. Below are example handle models available at extra cost:

HOPPE SECUSTIC security handle with a key and with a push button

Modern stainless steel handles from TUPAI

Astragal bars give a similar visual effect to solid glazing bars but differ in how they are fitted. A so-called “dummy spacer bar” is placed inside the glazing unit, and decorative timber strips are glued onto it from the outside, visually dividing the glass into smaller panes.

Price of stick-on glazing bars

ABA Wiktorczyk offers two types of stick-on glazing bars – the STANDARD astragal bar and the RETRO astragal bar. The price of bars glued onto the glass depends on their type, size and the timber species used – every order is priced individually. If you would like to place an order or find out more about the advantages of stick-on bars and the differences between the types, please get in touch.

See also:

• solid glazing bars
• internal Georgian bars (fixed)
• glazing bar frames

Removable glazing bar frames are used only in timber windows. Their biggest advantage is that they can easily be removed when the windows are cleaned. They are mounted on small hinges and catches that make them easy to open, and fitted on the outside of the window. Because they take less work to make, they are the cheapest option among timber glazing bars. If tastes or fashions change, they can always be removed, changing the look of the window.

Price of windows with glazing bars

The cost of glazing bars is calculated as the number of panes the window will be divided into × the set price per bar.

See also:

• solid glazing bars
• internal Georgian bars (fixed)
• astragal bars (glued on)

Proper ventilation is key to a good indoor climate in your home.

Our windows have two seals, which ensure the right airtightness and sound insulation. The seals are made of a material resistant to ageing, weather and contact with paint.

The seal is not glued in, so it can be taken out and replaced at any time if necessary.

Micro-ventilation

Micro-ventilation, also known as the night vent position, deliberately unseals the window slightly. It is achieved with special hardware components fitted to the sash and frame: just turn the handle 45° upwards from the horizontal position and pull the top edge of the sash towards you. A small gap then opens between the frame and the sash, through which outside air starts to flow in.

Although micro-ventilation does not replace proper airing (opening the window fully), it is worth remembering that using it helps to prevent damp and condensation on window panes and walls, especially in buildings with an inadequate ventilation system. When using micro-ventilation, however, remember that the unsealed window is not securely locked and may tempt burglars. It is therefore better to close the windows before leaving home – especially if they are easily accessible from outside, e.g. on the ground floor.

Trickle vents

In addition to micro-ventilation, which is standard on our windows, the windows can be fitted with trickle vents at extra cost.

We recommend the Aereco humidity-controlled trickle vent, which automatically adjusts the air flow to the humidity level in the room. When the humidity in the room falls, the vent closes.

The vent opens when the water vapour content of the air rises, i.e. when humidity increases. The vents are fitted in the top part of the window. Even with the windows tightly closed, they supply fresh air continuously, in the amount required by current regulations.

Besides their many advantages, trickle vents also have drawbacks. Their rather unattractive appearance, both inside and outside, cannot be ignored. Because of the limited range of colours, the vent cannot be matched to the colour of the joinery.

Under current regulations, windows supplied to the Polish market should have trickle vents wherever the building has no mechanical ventilation. The type and capacity of the vent are decided by the client on the basis of the building’s ventilation design.

We offer a wide choice of window boards and sills for our windows, which complement the interior design and bring out the style of the façade.

Internal window boards

• timber – a natural look and warm character, ideal for classic and modern interiors – available in two thicknesses, 3 cm and 4 cm, and two finishes (straight or with a routed edge),
• stone – exceptional durability and elegance, ideal for modern interiors.

External sills

aluminium – weather-resistant, durable and attractive for any façade.

We make sure the window boards and sills fit the chosen windows precisely and are finished to a high standard.

Ask about the colours available!

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We also offer high-quality fly screens made to fit our windows, which keep insects out effectively while letting air flow freely.

• precise fit to the windows
• solid, durable construction
• fine, unobtrusive mesh that does not restrict the view
• various systems and colours to choose from, to match the style of the joinery

Fly screens let you air rooms without letting insects in, keeping your home comfortable.

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