Buying Guides · updated 2026-10-29

Peephole Cameras: Digital Door Viewers for Flats Explained

With the clocks gone back and darkness falling by late afternoon, more people want to see who is at the door before opening it. If you live in a flat, a standard video doorbell is not always practical. You may have no doorbell wiring, the corridor may belong to the housing association, and drilling into the outside wall may not be allowed. A peephole camera, also called a digital door viewer, is often the simplest answer. It replaces the small glass viewer in your door with a camera on the outside and a screen on the inside.

This guide explains how peephole cameras work, how they differ from video doorbells, how to check that one will fit your door, and which features are worth paying attention to.

What Is a Peephole Camera?

A peephole camera has two parts joined through the existing peephole hole. A small camera module, often with a doorbell button and motion sensor, sits on the outside of the door. An indoor unit with a screen is mounted on the inside. Many models also connect to Wi-Fi and send alerts and live video to a smartphone app, so you can see who is outside even when you are not at home.

Because it uses the hole that is already there, installation usually needs no drilling, no wiring and no changes to the outside of the building. The units are normally powered by a rechargeable battery in the indoor part.

There are also two practical benefits that people often overlook:

• Easier for everyone in the household: children, older relatives and wheelchair users can see the visitor on a screen without bending down or standing on tiptoe.
• Nothing gives you away: a traditional peephole can show a shadow or a change in light when someone looks through it. With a screen, the visitor cannot tell whether anyone is watching.

Peephole Camera or Video Doorbell?

Both let you see and often speak to visitors, but they suit different homes.

• Peephole camera: best for flats and apartment buildings, rented homes and doors that open onto a shared corridor or stairwell. It needs no outside mounting, and it leaves almost no trace when removed, which matters if you rent.
• Video doorbell: better for houses with a front door that opens outside, especially if you want a wider view of the drive or path, a wired power supply or integration with an NVR or a larger camera system.

A peephole camera sits at the height of the viewer, so its view is usually of the person standing in front of the door rather than the ground. That makes it less useful for watching parcels left on the doormat. If deliveries are your main concern, check the camera's field of view and mounting height before buying.

Will It Fit Your Door?

This is the most important check, and most returns come from skipping it. Every peephole camera is designed for a specific range of hole diameters and door thicknesses. Before you order, do the following:

1. Measure the door thickness at the peephole, including any decorative panels or trims.
2. Unscrew the existing viewer and measure the diameter of the hole. Most viewers unscrew from the inside. A coin or a wide flat-blade screwdriver usually fits the slot.
3. Check the height of the hole and whether there is enough flat space around it on the inside for the indoor unit. Door handles, locks and decorative mouldings can get in the way.
4. Compare your measurements with the ranges given in the manufacturer's specifications. Do not assume a model will fit just because it fitted a neighbour's door.

If your door has no peephole, you would need to drill one. On a rented flat or a building-owned entrance door, ask for permission first. Many flat entrance doors are also fire-rated. Drilling or modifying them can affect their certification, so check with the housing association or building manager before making a new hole.

Features That Matter

Peephole cameras vary a great deal in quality. These are the features that make the biggest practical difference.

Screen and Picture Quality

A larger indoor screen is easier to read at a glance, especially for older users. The camera itself should give a clear image of a face at close range. A wide-angle lens helps you see people standing to the side of the door, but very wide lenses can distort faces at the edges.

Night Vision

Stairwells and corridors are often dark, particularly when the lights are on a timer. Infrared night vision lets the camera show a black-and-white image without any light. At this time of year it is essential, not a luxury.

Motion Detection and Alerts

Many models use a PIR (passive infrared) sensor or other motion detection to wake the camera when someone approaches. In a busy shared corridor this can cause frequent alerts. Look for adjustable sensitivity and the option to turn motion alerts off so the camera only reacts to the doorbell button.

Recording and Storage

Check how the camera stores clips. Common options are a microSD card in the indoor unit, cloud storage through the manufacturer's app, or both. If you choose a microSD card, use a reputable card designed for continuous writing, and format it in the device before first use.

Two-Way Audio and Doorbell Button

With two-way audio, you can speak to a courier or tell a visitor you will be a minute, without opening the door. A built-in doorbell button is useful if your flat has no working bell.

Battery Life

Battery runtime depends heavily on how often the camera wakes up. Frequent motion events, long live-view sessions and Wi-Fi streaming all drain the battery faster. Many units can be recharged with a USB cable without being removed from the door, which is much more convenient.

Wi-Fi in Stairwells and Metal Doors

Most connected peephole cameras use Wi-Fi, usually on the 2.4GHz band because it reaches further than 5GHz. The Wi-Fi radio sits in the indoor unit, inside your flat, so the signal is normally fine if your router is not too far away. Problems can still occur when:

• the router is at the opposite end of a large flat, behind several walls;
• the entrance door is made of steel, which can block or weaken signals near the indoor unit;
• many neighbouring networks crowd the same channels, which is common in apartment blocks.

Before installing, stand at the door with your phone and check the Wi-Fi signal strength. If it is weak, a mesh node or Wi-Fi extender in the hallway usually solves the problem. A poor connection leads to slow alerts, delayed live view and faster battery drain.

Privacy and Building Rules

A peephole camera in a flat almost always looks into a shared space: the corridor, the stairwell or a neighbour's door. Under European data protection rules, filming shared or public areas means you need to be careful about what you record and why.

• Record only what you need. If possible, use motion recording rather than continuous recording, and avoid aiming at a neighbour's front door.
• Use privacy masks if the app supports them, to block out areas you do not need to see.
• Do not keep footage longer than necessary, and keep access to the app limited to your household.
• Check the house rules. Some housing associations have their own rules about cameras in common areas. A short conversation with the board or your neighbours avoids disputes later.

Live viewing when someone rings the bell is generally less sensitive than continuous recording of a corridor. If you are unsure, your national data protection authority publishes guidance on home cameras.

Installing a Peephole Camera Step by Step

1. Charge the battery fully before installation and set up the device in the app, if it has one, while it is still on the table.
2. Remove the old viewer and clean the hole and the surrounding door surface.
3. Feed the outdoor camera's cable or connector through the hole from the outside, taking care not to pinch or kink it.
4. Fit the mounting plate on the inside and tighten the fixing sleeve until the outdoor camera sits firmly and straight. Do not over-tighten, as this can damage the door surface.
5. Connect the cable to the indoor unit and attach it to the mounting plate.
6. Test the picture, night vision and alerts with the corridor lights both on and off. Adjust the motion sensitivity if it is triggered by people walking past.

Keep the old viewer in a safe place. If you move out or change the camera, you can refit it and leave the door exactly as you found it.

Conclusion

For flats and apartment buildings, a peephole camera is one of the easiest ways to see who is at the door, particularly during the long, dark months ahead. It needs no wiring, leaves the outside of the building untouched and suits renters well. Measure your door and peephole hole carefully, choose a model with good night vision and sensible motion settings, check your Wi-Fi at the door and respect your neighbours' privacy. Do this, and a small device will make answering the door a lot more comfortable and secure.