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Darken Windows - Instructions DIY Ideas to Darken

  • preparation
  • Darken the window
    • aluminum foil
    • paper
    • Apply foil
    • insulation boards
    • insect
    • curtains
    • rolls

A darkened window is not only important for your daily sleep. In summer, the sun can be locked out, which would otherwise heat the room unpleasantly and who wants to enjoy privacy, can protect itself by the darkening from strange eyes. If you do not want to or can not rely on expensive blackout solutions, you should help yourself with one of the numerous DIY ideas.

A restful sleep is important for humans and animals. It gives strength, maintains health and makes for a good start to the day. But there are many obstacles that counteract the sweet dreams, such as the long summer days, traffic or annoying views from the outside. For this reason, it is worthwhile to darken windows with DIY solutions so that you can sleep well, even during the day. In addition, darkened windows effectively counter stagnant heat in the summer.


Before you use any of the following ideas to darken, you should first measure your windows. As soon as you have the appropriate dimensions, you can specifically and, above all, quickly select suitable articles that are suitable for the darkening solutions. You need this:

  • Measuring tape, folding rule or tape measure
  • Paper or notebook
  • Pen, for example pencil

Although you could easily use the windows as a template, some materials are easier to work on a table. When measuring, proceed as follows:

1. If you choose a DIY solution where fabrics are hung over the window, you should not just measure the window. Take the meter and measure the height and width of the window frame. Add to the width at least ten to fifteen centimeters on each side. You should also add ten centimeters to the top in case you decide to use roller blinds or curtains. These centimeters are needed for assembly.

2. For solutions that are applied directly to the glass for darkening, you should only measure the glass. Be very specific, because even small inaccuracies provide light or glued window frames.

3. Write down the measurements for both variants, so that you have them at hand when it comes to choosing the materials for implementing the ideas for darkening.

Darken the window

aluminum foil

It may seem weird, but aluminum foil has proved itself to be dark among the DIY ideas. Not only does this disturbing light stay away from the outside, but also heat, as the film has an insulating effect. Since aluminum foil can be found in virtually every household, this method is one of the simplest forms for darkening the windows. The aluminum foil works particularly effectively for smaller windows or those that are round or triangular.

Proceed as follows:

  • cut off a correspondingly large piece of aluminum foil
  • In doing so, orient yourself by the dimensions of the pane, not the window frame
  • Be careful not to tear the film
  • even small cracks can let in a lot of light
  • for larger windows cut out several parts
  • put the aluminum foil on the windowpane
  • Place several pieces of film in such a way that they overlap
  • the glossy side must point outwards as the dull side attracts heat
  • attach the aluminum foil to the window frame with adhesive tape or masking tape
  • also glue the overlapping foils
  • Make sure that there are no gaps to the frame


The use of thicker paper in the colors black and white is just as effective as the film, only more pleasant in the room. Together they have a sun-repellent effect. All you need is paper of the right dimensions, the two colors and at least the paper thickness of 100 g / m², as this is not opaque:

  • cut both papers just like the aluminum foil
  • these must be identical for darkening to work
  • first attach the white paper to the disk
  • For this you use adhesive or masking tape again
  • then place the black paper over the white one, pointing it inwards
  • The white paper does not seem too bright through the black paper as soon as the sun shines on it
  • fix the black paper

Depending on the design, you can stick decorative paper on the black paper, which is very suitable for children's or living rooms. So you do not have to settle for a pitch-black window.

Apply foil

Another variant for darkened windows is the application of an adhesive film. There are numerous designs and types of foils to buy in the hardware store that you can use for this purpose - frosted glass, monochrome foils or patterned foils

In this tutorial you will learn in detail how to obscure windows with foils: Apply window foil

insulation boards

A not necessarily appealing variant to darken windows is the use of insulating panels. These are actually used in house construction, but can be used quickly dimming DIY method to darken. Obtain an insulation plate in thickness (thickness), which corresponds to the distance from the glass to the highest point of the window frame. Then proceed as follows:

  • use a cutter to cut the insulation board to the size of the window pane
  • Be careful not to cut too much as this size must be right
  • then press the plate onto the pane so that it is fixed by the frame alone
  • do not fit them right in, should you cut something else and try again

A big advantage of this variant to darken is the fast assembly and disassembly. Within a few easy steps you have pressed the plate into the window frame and can release it carefully with a Phillips screwdriver. Despite the unattractive aesthetics, the plate provides a dark space and you can store it anywhere, as soon as it is not used. Please do not use styrofoam or foam panels, as they are not optimized for high heat development by the sun.


Fly screens are perfect for darkening windows. Due to the thin mesh structure and dark color they provide a weak protection against light, which is not difficult to assemble and can be removed at any time. In addition, they protect against annoying vermin, which is a blessing in the summer. For this you should choose a fly net, no grid, in the darkest version and fix it as follows:

  • Cut a piece of the fly net to the desired size
  • this should be enough on all sides an inch on the window frame
  • The net is now fixed at the upper corners
  • For this you either use a strong adhesive tape or a stapler
  • Smooth the net up and fix this part as well
  • Now the procedure is the same with the sides
  • the lower two corners are fastened last and then the lower side attached

Alternatively, you can simply mount the net on the outer frame. At the same time, you benefit from insect protection.


Curtains have been standard for decades when it comes to darkening windows. They are easy to make or purchase themselves, provide an aesthetic aspect in the room and darken windows well. Here, the thicker the curtain is, the more effective. If you do not want to buy a curtain, you can make it yourself. For this you need:

  • Velvet or cotton fabric, also coated, in the width of the window
  • sturdy yarn
  • Sewing utensils or sewing machine
  • shears

The darker the fabric, the better the darkening properties. You can choose a motif fabric or a dark color that also matches the ambience. Following the instructions:

  • cut the fabric to the desired length
  • make sure that it reaches completely to the bottom
  • so you block out extra light that shines on the floor
  • clean up the entire fabric
  • Place the curtain rod at the top of the curtain
  • Beat the fabric around the pole and fix it with safety pins
  • The pole should not be over-tightened, rather loosely in the loop
  • sew the loop thoroughly
  • take the rod out again
  • This will keep it longer
  • Now you have your curtain at hand

This is the simplest version of a curtain. Of course, you can also sew individual loops at regular intervals, but as a privacy screen, a continuous loop is also available. If you want two curtains, cut the curtain into two pieces in the middle before overcasting and proceed as described above for both parts.


If you do not want to tinker yourself, you should buy one of the many, quite cheap roller blinds. Depending on the model, these are mounted above or directly on the window frame and darken the room well. The following types are used and are different effective for darkening:

  • Bamboo blind: Sun usually penetrates between individual bamboo sticks - costs: about 15 euros
  • Plissee: good for darkening, usually a little brighter than other variants, opaque - costs: 12 - 30 euros
  • Faltrollo: very good for darkening, darker than the pleated blind, opaque - cost: 20 - 40 euros
  • Spring roller blind: extremely well suited for darkening, opaque and almost completely darkening - cost: 30 - 60 euros
  • Blackout blind: better version of the Spring Rollos, as soon as the quality is right, completely opaque and darkening - Cost: 30 - 200 euros, depending on quality and size

If you opt for a roller blind, you should follow the instructions of the manufacturer during assembly. Lightweight roller blinds such as bamboo or pleats are usually fixed with screws or nails, while blackout or roller blinds have to be mounted differently from manufacturer to manufacturer.

Tip: Combine a roller blind with curtains to darken the window more efficiently. To do this, you should attach two separate curtains to the sides of the roller blind so that they can prevent any possible incidence of light.

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