Door viewer: see for sure who is ringing.

Seeing who is at the door without opening it: Door viewers are primarily used for security and burglary protection. Whether classic wide-angle lens or digital with display/app: Here you can find out about types, installation, height, viewing angle and what you should look out for in data protection and apartment buildings - in a compact and practical way.

Everyone is familiar with the conventional door viewer: a hole in the door at eye level - usually with a flap to close it. Current models are equipped with a wide-angle lens that increases the detection angle to 100 to 200 degrees. The concave lens prevents anyone from outside from looking into your home.

In the classic door peephole, the peephole is located in the upper door leaf area. Since there are no mechanical wear parts attached, the classic door peephole is built to last forever. Thanks to this feature, it is now standard in the entrance doors of most rental apartments. Disadvantage of the door peephole: the area outside the door must be illuminated in the evening or in poor lighting conditions in order to be able to recognize something or someone.

Alternatives to the door peephole are door chains or locking brackets as protective hardware, which are rarely found today: They allowed to open the door only a crack. If someone presses against it from the outside, the chain or the locking bar resists.

1. Select type:Optical (low-cost, low-maintenance) or digital (display/app, optional night vision).
2. Check viewing angle: Wide angle ~100-200° covers the entrance area better.
3. Door thickness & installation: Consider compatibility with door leaf thickness; digital → plan for battery/power supply.
4. Determine height: Install at eye level (see "Height" section). Lower if necessary for barrier-free doors.
5. Legal & data protection: In apartment buildings, always involve the landlord/building management (especially with digital models/recording).

In your own home, you can optimally integrate the digital door viewer into an existing smart home system. For example, there is the option of coupling door viewers with voice communication - similar to an intercom system - so that the resident can talk to the visitor. By connecting to a smart doorbell or smart door opener, the door can then be opened as needed. For higher burglary protection or night owls, an outdoor camera with infrared motion detector is also suitable. The disadvantage: Depending on its sensitivity, the motion detector also registers movements of larger animals. You should bear this in mind for houses on the edge of a forest.

Smart Home requires a WLAN signal, so a WLAN router with the appropriate range should be available.

With the help of a smartphone, you can access the door viewer while on the move. If the door intercom is linked to other elements, you can open the door, start the ventilation or control the light in the entrance area while on the move. For example, if the children are coming from school, tradesmen have been announced, or the letter carrier is to leave a package at a drop-off point, these functions prove helpful.

Classic peephole (optical)

• Plus: Inexpensive, low-maintenance, concave lens protects privacy.
• Minus:Poorer view in twilight/shade, you have to go to the door.
• Who for: Rented apartment, easy to retrofit.

Digital peephole

• Plus:Display/app, partly night vision, recording possible.
• Minus:Battery/battery, higher costs, observe data protection.
• Who for: Owner-occupied home, convenience/accessibility.

Door viewers are used not only in the private sphere, but also by the police or banks, for example, to view a vault. Prisons also use door viewers to keep an eye on prisoners from the outside.

The door peephole varies in height. Particularly in barrier-free apartments, a classic door peephole can also be installed significantly lower than usual. The standard height in Germany is 140 cm - measured from the lower edge of the door leaf..

The classic door viewer is a standard feature in most rented apartments and, thanks to its long service life, can usually remain in the door until a new tenant moves in. In your own home or condominium, it is best to consult a professional for installation. This guarantees that the door peephole is firmly fixed, so that the security of the door remains guaranteed. Cost for the classic door viewer: from 10 euros plus installation.

The digital door viewer always requires professional support. Particularly in the case of integration into a smart home system, the expertise of the experts is crucial. They provide instruction in the functions and expertly answer all questions. Digital door viewers can vary in price from around 70 euros to several hundred euros.

You can find the right door viewer in a DIY store, department store or specialist security technology store - or online. Ask for advice in a specialist store. If necessary, the dealers also offer an installation service.

By the way: As a tenant, you are allowed to install a door viewer in the entrance door of your flat - without the landlord's consent. This was decided by the district court of Meißen in its door viewer ruling (ref. 112 C 353/17).

Door viewers, also known as peepholes, are small but effective security devices that allow you to see visitors from the inside before you open the door. Choosing the right Door viewers can greatly improve your home security. Here are some important Spots to consider before and when buying a Door viewer:

What questions are most often asked about door viewers? We found out using software that analyses which questions people ask voice assistants from Apple, Google and others. We answer three of them here:

Optical models often start in the low double-digit range (plus mounting). Digital models start higher - depending on display/app, night vision, recording.

At eye level - in many households ~140-160 cm from the floor. Lower if necessary in barrier-free homes. Important: a clear view without stretching.

A mini camera in the door leaf provides the image on the display or smartphone app; some with nightvision/storage. In apartment buildings, clarify rights/data protection in advance.

Tip for tenants: In the case of optical models, there are judgments that allow installation without consulting the landlord; nevertheless, the following applies: check the individual case + house rules and consult the landlord - especially with digital solutions/recordings.

Before you commit yourself, check the visibility conditions in front of the door: a wide viewing angle only helps if the corridor geometry and light play along. If possible, install lighting with a motion detector opposite the door so that faces do not disappear in the backlight. Think about contrasts: dark doors with a black peephole look elegant, but can darken the image on the inside; a light-colored decorative ring can improve legibility. Test the location with a provisional drilling template (cardboard with a hole) at the eye level of all main users and simulate the viewing angle towards the stairwell or elevator - often an offset of a few centimetres makes a difference to a much better overview.

For outdoor or cold stairwells, it is worth taking a look at insulation and draughts: models with a covering flap or return spring minimize heat loss and prevent draughts; an anti-spy coating makes it difficult to spy from outside. For digital versions, pay attention to battery and power routing, a secure mount to prevent twisting and data protection (no permanent recording of communal areas, clear user rights). After installation, plan a short maintenance routine: clean the glass/lens occasionally with a microfiber cloth, retighten the screw connections after a few weeks, check the sealing lips - this will keep the view clear and the function permanently reliable.

If doors are used by very different people (children, senior citizens, wheelchair users), a multi-height strategy is worthwhile instead of a "mean value": Either two stacked peepholes (top/bottom) or a panoramic/prism peephole with an extended field of vision that provides clear images even when the head is tilted. The lateral offset to the edge of the door is important so that even seated people can see without twisting their upper body. Also plan an easy-to-grip inner cover (no fiddly flaps) and a high-contrast decorative edge color that makes the peephole easy to find in twilight. Larger eyepieces and models with anti-reflective lenses prove their worth in households with fine motor skills impairments because they require less precise eye positioning. This creates accessibility without sacrificing safety, discretion or design.

A door viewer is a small but effective opening in a building component: if not designed correctly, it can promote cold bridges, draughts or rattling noises. You should therefore look for models with a circumferential sealing lip, thermally decoupled sleeves and a tight-fitting inner cap. For external doors or cold stairwells, a resilient cover reduces air exchange; avoid condensation on the lens by ensuring a flush fit without a gap and choosing non-condensing surfaces (silky matt instead of high-gloss). When installing, check the material pairing (steel/wood/aluminium) and decouple metallic contacts to minimize contact corrosion and structure-borne noise. A short pressure/noise test after installation (interior quiet, door gap closed) shows whether the design is tight and quiet - this keeps the peephole secure, quiet and inconspicuous in terms of energy.