Windows are available in a wide range of colors, sizes, and styles. Therefore, it’s important to carefully consider which window type suits your needs and your building. Let us explain the differences.

Whether made of wood or plastic, with insulating glass and sound insulation – windows play an important role in building construction.

Before you decide on a window type, it’s important to do your research. A basic differentiator between windows is how the panes sit in the sash and how they can be opened. Here are the most common window types.

Single Window

Single windows are most common, they consist of sash frames and window sashes. The energy-saving two or three-pane glazing is installed in each sash, air-tightly connected to each other.

Composite windows consist of a separate outer and inner sash with single glazing. The sashes move on a common hinge and hook together on the opposite side using a fitting. This can be released with a special key so that the inside of the panes can be cleaned.

Due to the low weight of the panes, composite windows can be built as slender lattice windows with traditional window divisions. This is particularly true to style in old buildings.

Box Windows

Box windows have separate sashes inside and outside, which can be opened and closed separately. They sit in a surrounding lining at a distance of up to 6 inches; the complete set looks like a box.

The outer wing usually opens to the outside, the inner wing to the room side, the wings can be fitted with different types of glazing. Heat insulation glass is often chosen for the outside and inexpensive single glazing for the inside. In some buildings, the single glazing is also sometimes placed in the outer wing.

Box windows are very popular because of their good sound and heat insulation.

Opening Types

A distinction is also made between how windows are opened. This is because the type of opening has an influence on how the windows are used.

The following questions can help with window selection: Can they be easily opened for ventilation, can I put the decoration in front of them, how well can they be cleaned and can a shade be added afterward?

Fixed Glazing

Fixed glazing is the least costly solution, but means that the window cannot be opened. Fixed glazing is used, for example, as facade decoration and combined with rotating window sashes in multi-part windows or as skylights.

Rotary Wing

Rotating leaves rotate around a vertical axis at the left or right edge.

Tilt Sash

Tilting sashes have a lower horizontal axis and open a gap at the top. If the axis is located at the top, for example at a skylight, one speaks of a folding sash.

Turn-tilt Wing

Turn-tilt sashes are among the best-selling window types: the sash can be turned or tilted. On older models, you need both hands to turn the fitting, modern fittings allow operation with only one hand.

Sliding Windows

Sliding windows and doors are lifted by turning the handle or swiveled out of the guide rail and can then be moved sideways.

Swing Windows

Swinging windows revolve around a horizontal central axis, one part of the sash protruding into the room, the other outside. If the window sash moves around a vertical axis, this is called a turning window.

Note: Combinations are also possible, such as a two-wing window with skylight and tilt and turn sashes or a skylight for tilting with a lower part as a turning sash.

Whatever you choose, two things are extremely important: the window should be accessible without having to climb up and ventilate the room transversely.


The glazed area of a room must be 1/8 to 1/3 of the room floor area – there are no regulations for the size of individual windows. Standard dimensions, also known as preferential dimensions, are becoming less important.

The dimensions and profiling of the frame timbers, on the other hand, are standardized, from which all types of windows can be produced at low cost – even with special profiles, bar spacings and special shapes such as arched windows or triangles. Aluminum panels on the outside of the frame protect the wooden surface from the weather, while thermal insulation materials in the core improve the energy balance.

The Right Frame

Wood-aluminum Windows

Wood-aluminum windows combine the technical advantages of aluminum and the design advantages of wood: on the outside, a robust aluminum shell protects against wind and weather, inside you can enjoy the cozy atmosphere of wood.

The aluminum is largely weather-resistant and shows hardly any signs of aging or wear, even after years of use. Since wood and aluminum expand differently with temperature and humidity fluctuations, the materials must be joined together in a certain way. Usually, the aluminum is not screwed onto the sealed wood but clipped on using a special clip. The fact that there are no contact points fixed at specific points gives the materials the necessary leeway to move.

Wooden Windows

Suitable wood for windows is spruce, pine, larch, fir, oak or meranti. There are also windows made of precious wood such as maple, alder, cherry, and walnut as well as teak and even mahogany. Wood ages over time and must be regularly cared for to ensure that it lasts as long as possible.

Although wooden windows are more sensitive to moisture, frost and UV rays, they are still extremely popular. Not only can they be treated with any color and thus redesigned, but they also convey a special warmth and comfort in the living room. Wood is also a renewable resource and therefore a good choice for environmentally conscious owners. Because wood binds carbon during growth. Who uses the material thus on a long-term basis as a building material, reduces the greenhouse gas carbon dioxide (CO2).

It is important to apply a wood preservative; this process can already be carried out during the manufacturing process. The wood is impregnated and coated all around, which also protects the hidden inner edges of the corners from penetrating moisture. A triple paint structure extends the durability of the paint application.

Plastic Windows

Plastic windows are by far the cheapest choice. They are not only easy to clean, but also have a long service life without surface treatment. Weathering, corrosion, acids, exhaust gases, and cleaning agents are of little importance to them.

Thanks to the easily moldable PVC, plastic windows are available in all shapes and colors. For an extra charge, they are even available with decor.

Although plastic windows are much cheaper, they are in no way inferior to wooden windows in terms of heat and sound insulation. However, they are statically charged and attract dust. Also, plastic provides a cooler living atmosphere and the production of PVC is considered to be less environmentally friendly.

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