New roof windows: costs for material and installation

Depending on the equipment roof windows can be a very expensive purchase. For this purpose, a sufficient number of skylights must be installed especially in used as a living room attics. With how many skylights you can expect, and what costs can be incurred for a skylight, you will learn in detail in this post.

prime example

In our example, a manually operated hinged swinging windows have been supplied by the roofer and, including an aluminum roofing frame, can be installed in the roof. The roof is covered with clay roof tiles. Our skylight should be 850 x 1450 mm in size and recessed. For this purpose, it is provided with a manual external shutters shutters.

skylight568 EUR
flashings255 EUR
shutters330 EUR
Total price (including installation)1,153 euros


Details about the skylight and the equipment selected by us can be found in this service description.


Note that our skylight is just a prime example of a skylight that was sourced and installed by the roofer. Depending on the manufacturer, the window design and the local conditions in your house, prices for skylights and installation may be significantly different. In particular, with cheap sources of supply for your window, such as windows from Poland, the prices for the window can sometimes be up to 20% lower, but you often have to pay more for delivery and installation.

New roof windows: costs for material and installation: roof


When installing a roof window must be sealed both from the outside, as well as inside connected to the existing insulation and connected to the vapor barrier tight and tight. From the outside, the connection to the roofing is usually done with a roofing frame, which can be made of different materials. The connection inside is made by airtight connection with the vapor barrier and a jointless connection with the thermal insulation. In the roof window area, it is particularly important to work very accurately - if thermal bridges in the window area, severe moisture damage in the roof area may threaten, then mold in the insulation layer. Often these damages are not immediately recognizable, and therefore all the more dangerous.

Correct window size and according to state building regulations

There are also regulations for the number of skylights required and the correct window size in Germany. It can be used both the state building regulations, as well as the DIN. According to the state building regulations, the size of the areas of light in a room must be at least 8% (in some federal states also 10%) of the floor area of ​​the room.

Correct window size according to DIN

According to the DIN, the room width is used to measure the window areas. The width of all existing skylights taken together should be about 55% of the room width. The room width is always the longer side of the room. This method often yields slightly lower values ​​than the area values ​​of the state building regulations, but can also be used well for the approximation. Inclined windows also allow more light into the room than vertical windows and also lead to better ventilation.

Price differences in the skylight

window dimensions

Of course, roof windows have different costs depending on the dimensions. With the same design, the cost of roof windows can vary significantly depending on the size, as the following table shows:

window sizeprice
850x1450about 520 - 720 EUR
600x860about 350 - 470 EUR
1140x 2010about 780 - 1.170 EUR

Individual measures that have become established as "standard measures" and are often demanded or planned can sometimes be a bit cheaper than others of similar size. This is because these windows are often produced "in stock" by many manufacturers, thereby reducing production costs. In addition to the window size, however, especially the design and the equipment of the window plays an important role. This includes:

  • Frame material (wood, plastic, wood-plastic)
  • Window mechanism (fixed, hinged window, swing window, hinged window, electrical operation) and especially the
  • Quality of the glazing (U-value, glass properties)

window material

Skylights are often made of wood, often with an additional heat-insulating frame, which should make a better insulation of the window frame possible. In the following table we have compared the price differences for different insulation materials (with identical window design).

window materialprice
PVC-U, thermally insulated520 - 710 EUR
Wood590 - 810 EUR
Wood, thermally insulated factory570 - 780 EUR
Wood-Plastic590 - 815 EUR
Wood-plastic with additional insulation frame650 - 880 EUR

Quality of the glazing

Window glazing is mainly distinguished by the U-value of the windows. But there are also special glass properties, such as a solar radiation reducing coating or hail protection. Compare in our table below:

glass versionprice
Multi-pane insulating glass, U-value 0.9, sun and hail protection (example)520 - 710 EUR
Without sun and hail protection470 - 650 EUR
Only sunscreen510 - 700 EUR
gl. window like pattern, U-value 1,1470 - 650 EUR
gl. window like pattern, U-value 0.8530 - 730 EUR
gl. window like pattern, U-value 0.6570 - 780 EUR
gl. windows like pattern, total energy transmittance less than 25 (pattern: 25 - 35)540 - 740 EUR

Cost of accessories

Of course, the cost of accessories always depends on the window size. With reference to our sample window (850 x 1,450 mm), you can assume the following recommended prices for accessories:

Additional equipment for our windowprice
indoor blind90 - 130 EUR for our sample window
Wooden or plastic window board 30 cm wide170 - 230 EUR for our sample window
Insect screen100 - 130 EUR for our sample window
blackout blind90 - 130 EUR for our sample window

Conservative factors

  • average U-values ​​(with skylights usually 1.0 or 1.1 W / (m · K))
  • mechanical operation
  • Windows in the "standard measure"

Increasing factors

  • electrical operation and control
  • additional protective properties of the glass (sun protection, hail protection)
  • high-quality window designs
  • Accessories to the window

Saving opportunities through self-construction or personal contribution

The installation of a roof window requires a lot of expertise and experience. Even the smallest errors during installation can cause severe damage to the window and in the entire roof space (moisture damage, thermal bridge formation, subsequent mold infestation). From a self-installation is therefore strongly discouraged.


Numerous subsidies are available for the replacement of old skylights, but also for a correspondingly energy-efficient loft conversion. Information on possible funding and how you can claim the cost of working in income tax can be found in our general funding overview.

Tips & Tricks

Make sure you compare the prices at Dachfenstern, and make sure you make several offers. Especially with roof windows from Poland, remember that it might be difficult to enforce warranty claims, and always pay close attention to additional costs (delivery, installation).

Video Board: 100+ Year Roof Options