Installing a video doorbell on your existing bell wiring works in almost every home, but the standard 8 volt bell transformer is too weak for a lot of models. Wired video doorbells usually want 8 to 24 volts AC at 10 to 40 VA, and the heavier models need at least 16 volts. The fix is to swap the bell transformer in your consumer unit for an adjustable DIN rail transformer set to 12 or 24 volts. If you have a digital chime, it needs a diode across the terminals. With a mechanical chime or no chime at all, you use the supplied resistor or power kit. Never wire a video doorbell straight to 230 volts, that destroys it instantly. And mind the privacy rules: under data protection law your camera should in principle only capture your own home and your own property, and you have to limit filming of the public street and your neighbours’ gardens as much as possible.
Hello DIYer,
The box has arrived. Smart looking thing, costs anywhere from thirty euros to a few hundred, and the packaging promises you will have it up in fifteen minutes.
And then it is up. And then it half works.
The picture stutters. The chime in the hallway rings on and on until you switch it off. Or the thing keeps dropping out with an “insufficient power” message.
That is almost never the device. That is the part of the installation you cannot see: a transformer in the consumer unit that has been sitting there for thirty years, meant for a simple three euro bell push.
In this article I walk you through the whole job. From choosing to mounting, including the three points where it goes wrong for everybody: the transformer, the chime and the wi-fi. And after that, the bit missing from every manual, the bit data protection regulators now get hundreds of complaints about every year: what you are and are not allowed to film with a camera like this.
Here we go:
First choose: battery, wired or PoE
Three flavours, and that choice shapes the rest of the job.
| Battery | Wired (on a bell transformer) | PoE (network cable) | |
|---|---|---|---|
| Installation | Drill and hang, done | Check transformer, adapt chime, wire up | Run a network cable to the door |
| Power | Battery, recharge every 2 to 6 months | Continuous | Continuous, via the network switch |
| Continuous recording | No, motion only | Often yes, depends on the model | Yes |
| Response speed | Slower, it has to wake up | Fast | Fast |
| Works during an internet outage | No | No (unless local storage) | Yes, with local storage |
| Existing chime usable | Usually not | Yes, with a diode or resistor | No, needs its own chime |
| Hassle in a rented home | Little | Moderate | A lot |
| Device cost | 60 to 250 euros | 80 to 300 euros | 150 to 400 euros |
My plain advice: if you already have a wired doorbell, go wired. The cable is in place and you never have to charge a battery. Living in a flat with no bell wiring of your own running outside, or renting? Then battery is the path of least resistance. PoE is for people who already have network cable through the house and are determined to keep their footage local.
Check in 15 minutes whether your home is suitable
Do this before you order anything. Five checks.
1. Do you even have a wired doorbell?
Look in the consumer unit. Do you see a small block on the DIN rail or on the backboard, marked something like “8V 1A” or “8V 10VA”? That is your bell transformer. If it is there, there is bell wiring running to the front door as well.
No transformer, but the bell works? Then you probably have a wireless battery bell. In that case there is no cable running outside.
2. What voltage does your transformer supply?
It is usually printed on the transformer. If there is nothing there, or it is unreadable, you measure it.
Set a multimeter to AC voltage (VAC), take the existing bell push off the wall and measure between the two wires. That gives you the voltage your transformer supplies. In most homes you will see 8 volts, sometimes 12.
Note: what you are measuring here is extra low safety voltage, which is harmless. Do not measure on the 230 volt side of the transformer if you do not know exactly what you are doing.
3. How many VA does your transformer supply?
This is the number everybody skips, and the one that causes most of the faults.
Volts tell you something about pressure, VA tells you how much can flow through. An old fashioned bell push with a chime draws almost nothing, so old transformers are often lightly rated: 4 to 10 VA. A video doorbell is a small computer with a camera, a wi-fi chip, an infrared LED and a speaker, and it draws current around the clock.
Typical manufacturer requirements:
- Lighter wired models: 8 to 24 volts AC, 8 to 40 VA
- Heavier Pro models: 16 to 24 volts AC, 10 to 40 VA
- Battery models that trickle charge off the bell wiring: 8 to 24 volts AC, 5 to 40 VA
In short: if your transformer says 8V and a low VA figure, a heavier model is not going to run properly on it. Even if it seems fine at first.
4. What kind of chime is fitted?
Stand next to the chime and get somebody to press the bell.
- Do you hear a physical click or ding-dong from a little hammer striking two metal bars? That is a mechanical chime.
- Do you hear an electronic tune coming out of a small speaker? That is a digital chime.
This difference decides which little component you need. More on that in a moment.
5. Is there wi-fi at the front door?
Stand at the front door with your phone, on the outside, and look at your wi-fi signal. Do not forget: from the router’s point of view the camera sits behind your wall, and walls with insulation and foil damp the signal considerably.
Important detail: virtually all video doorbells only work on the 2.4 GHz network, not on 5 GHz. If your router uses one network name for both bands (band steering), you may have to split them temporarily to get the doorbell paired.
Unsure about the range? Budget for a mesh point or access point near the front door. That is a common extra of 50 to 150 euros that never shows up in the reviews.
Replacing the bell transformer: how to do it
If your transformer turns out to be too weak, this is the proper fix. Cost: 15 to 45 euros for a decent DIN rail transformer.
Which transformer do you buy?
Look for an adjustable bell transformer for DIN rail with several outputs, for example 8 volts, 12 volts and 24 volts. A transformer like that also gives a different power rating per setting, say 8V at 10 VA, 12V at 20 VA and 24V at 30 VA. Pick the setting your video doorbell asks for.
Rule of thumb: choose 24 volts if your manufacturer specifies 16 to 24 volts, and 12 volts if 8 to 24 volts is allowed and you want to keep using your old chime. At higher voltage a mechanical chime pulls harder, which sometimes gives a louder but also rougher sound.
A bell transformer is a safety transformer: it converts 230 volts to safe extra low voltage (SELV) with separation between the primary and secondary side. So buy a proper bell transformer, not some random power supply.
Wiring it up
The secondary side (the low voltage feed to your bell) is harmless work. The primary side is 230 volts, and that means working inside the consumer unit.
The honest answer: if you have never worked in a consumer unit, have an electrician fit the transformer. That is half an hour’s work and costs you 75 to 150 euros. Worth it too, because you are working on the supply side of a circuit that can be live. In England and Wales, work inside a consumer unit is notifiable under Part P of the Building Regulations, so this is not the corner to cut.
If you are doing it yourself, in short:
- Main switch off, then confirm it is dead with a voltage tester.
- Disconnect the old transformer. Note down or photograph how it was wired first.
- Clip the new transformer onto the DIN rail.
- Connect the primary side (line and neutral, 230 volts) behind a suitable protective device, in line with BS 7671.
- The secondary side: the two wires to the bell push and chime back onto the chosen voltage output.
- Power up and measure whether you have the right voltage at the bell push.
The chime: where it really goes wrong
This is the reason people go running into the consumer unit swearing after installation.
An ordinary bell push makes contact very briefly and that is that. A video doorbell sits in the circuit permanently and draws a small current permanently. That trickle can make your chime buzz, click or ring endlessly.
Mechanical chime
A mechanical chime usually needs a resistor or the supplied power kit (sometimes called a “chime kit” or “power supply kit”). It makes sure the doorbell gets enough current without the little hammer staying pulled in.
Where it goes varies by brand. With some brands you fit the resistor to the contacts on the back of the doorbell itself, with others you fit a small box inside the chime. Read the manual for your model, because a resistor in the wrong place gives you exactly the problem you were trying to avoid.
Digital chime
A digital chime needs a diode, and you fit it across the chime’s terminals. That diode only lets current through one way, so the electronics inside the chime are not being triggered continuously.
A diode has a direction. If it is the wrong way round nothing gets damaged, but your chime simply will not work properly. Turn it around and test again.
Not using the chime any more
Want to drop the old chime entirely and rely on a notification on your phone plus a separate indoor chime from the same brand? Then you take the chime out of the circuit and bridge the connection, usually with the supplied bypass connector or a piece of wire with a resistor. Same here: exactly as your model’s manual says, because the manufacturer knows what resistance value its device expects to see.
The cabling: what is already there and when it is not enough
Good news first: the thin bell wiring found in most homes is perfectly suitable. A video doorbell draws very little current, so the wire itself is rarely the problem.
What you do need to watch:
- Length. If the cable runs from the consumer unit through the crawl space and the hall to the front door, that can easily be 20 to 30 metres. With very thin wire over a long run you get voltage drop. Measure the voltage at the bell push, not in the consumer unit: that is the voltage that counts.
- Connections. Old, corroded connectors or twisted joints in a duct create contact resistance. While you are at it: remake the joints with a decent connector block.
- Getting through the wall. Is the old bell push on a wooden frame and do you want the new one on the brickwork? Then drill through the mortar joint with a masonry bit, not through the brick, and seal the hole with an exterior grade sealant. Drill with a slight fall towards the outside so no water runs inwards.
- Drilling into a cavity wall. Measure your drilling depth in advance and keep in mind that you do not want to push dust or sealant into the cavity.
Mounting: the spot decides whether your picture is worth anything
A video doorbell in the wrong spot gives you a beautiful recording of a hairline and a chin.
Height. Manufacturers usually recommend around 1.20 metres off the ground. That sounds low, but the lens looks upward, and then you get a complete face in shot instead of a nostril. Hang it at 1.50 metres and with a tall visitor you are looking at a forehead, and you will not see a parcel on the step at all.
Angle. If your front door sits in a recess or the door frame is at right angles to the approach, you are looking straight at a wall. Practically every brand supplies a wedge or angled bracket (usually 15 to 35 degrees). Order it at the same time, because moving a hole in brickwork afterwards is a waste.
Light. If your camera looks straight into low sun or at a bright street light, you get silhouettes in daylight. Turn the camera a few degrees away from the light source if you can.
Rain and splash. Under a canopy or an overhang is better. If it takes driving rain constantly, water ends up on the lens over time and the picture discolours. A rain shield costing a few euros works wonders.
Distance from the door. Do not hang it so close to the door that the door swings into shot, and not so far away that people cannot find it. Fifteen to thirty centimetres beside the door frame is a good spot.
Installation step by step
- Switch off the power. The main switch, or the circuit the bell transformer sits on.
- Take off the old bell push and photograph how the wires were connected.
- Measure the voltage at the bell push wires (multimeter on VAC). Note what you measure.
- Replace the bell transformer if needed in the consumer unit, or have it replaced.
- Fit the diode or the resistor at the chime, following your manual.
- Fit the mounting plate at the height you want. Drill into the mortar joint in brickwork, use plugs rated for outdoor use, and set the plate level.
- Connect the two wires to the doorbell’s terminals. With AC voltage the order does not matter.
- Click the doorbell onto the plate and fix it with the supplied security screw. Do actually do this: without that screw, somebody lifts it off in three seconds.
- Power up and pair it with your 2.4 GHz wi-fi through the app.
- Test everything: bell push, chime indoors, notification on the phone, two way speech and the night image.
- Set your detection zones (more on this in a moment, because it is not just handy, it is legally relevant too).
- Seal the cable entry and tidy up.
Are you allowed to film the street with a doorbell camera?
This is where it gets serious, and this part is missing from virtually every installation manual.
A camera on your wall falls under data protection law. Regulators are clear about it: your camera should in principle only capture your own home and your own property. Your neighbours’ gardens and the public street do not belong in that picture.
Complaints are climbing fast. For a sense of scale: the Dutch data protection authority received around 370 of them in 2024 and over 550 in 2025.
What does that mean in practice?
The household exemption does not simply apply. The GDPR has an exemption for purely personal use, but it falls away the moment your camera records public space or somebody else’s land. In the eyes of the law you are then a data controller, with everything that comes with it.
Limit what you film. If you cannot keep the pavement or a parking space entirely out of shot, you have to limit it as far as possible. You can do that physically with a shield or by aiming the camera differently, and digitally with privacy masking or detection zones in the app. Practically every brand has that function. Use it.
Keep footage briefly. You must not keep footage longer than necessary. Sensible options are having recordings deleted automatically or only viewing live, and a short retention period, 24 hours for example, counts as good practice. If nothing happened, there is no reason to keep anything.
Let people know you are filming. A sign or sticker saying “CCTV in operation” by the front door is the simplest way to meet your duty to inform. Costs three euros.
There are exceptions. If you have been burgled or are demonstrably being harassed, there can be a good reason to temporarily film a stretch of public street after all. Temporarily is the key word there, and write down why you are doing it.
Neighbours are entitled to challenge you. Neighbours who feel they are being filmed unfairly can ask you to stop, complain to the regulator and in the worst case take you to court. That is a thoroughly miserable process over a hundred euro device. A quick word with your neighbours beforehand prevents nine out of ten conflicts.
To be clear
This is not legal advice and the exact assessment depends on your situation. But stick to three things (aim at your own property as much as possible, use privacy masking for the rest, keep footage briefly) and in practice you will be fine.
Renting, or living in a flat?
Rented home. For drilling into the wall and altering the installation you need your landlord’s permission. Plenty of housing providers now have a camera policy with set conditions. Ask before you drill, because a hole in the wall is your problem when you hand the keys back.
Flats and shared buildings. The façade of a block of flats is usually shared property. Formally, that means you need permission from the freeholder, management company or owners’ association before you fix anything to it. In practice many are relaxed about a doorbell, but get it recorded in the minutes. And pay extra attention to the privacy side: in a shared entrance or on a walkway you are almost always filming your neighbours’ door too, and exactly the same rule applies there.
Costs at a glance
| Item | Range | Notes |
|---|---|---|
| Video doorbell | 60 to 300 euros | Battery cheaper, Pro models dearer |
| Bell transformer (DIN rail, adjustable) | 15 to 45 euros | Only needed if the existing one is too weak |
| Electrician for the transformer | 75 to 150 euros | Half an hour’s work, call out included |
| Angled or wedge bracket | 10 to 25 euros | Often indispensable |
| Rain shield | 5 to 15 euros | Extends the life of your picture |
| Mesh point or access point | 50 to 150 euros | Only with weak wi-fi at the door |
| Cloud storage subscription | 3 to 12 euros per month | Often per camera, sometimes per household |
| Local storage (base station or NAS) | 50 to 200 euros one off | Alternative to a subscription |
Watch that subscription when you choose. An 80 euro doorbell with a 6 euro a month subscription costs you 440 euros over five years. A dearer set with local storage can work out cheaper, and your footage stays in the house.
Common mistakes
- Wiring the video doorbell to 230 volts. Fatal, instant, and not covered by warranty. Video doorbells run on extra low voltage.
- Only looking at volts and not at VA. Your transformer gives 8 volts, so it “fits”. Until your model draws more current for night vision or a conversation than the transformer can supply and the picture drops out.
- Skipping the diode or resistor. Often works at first, then starts buzzing or ringing endlessly.
- Mounting it too high. Manufacturers recommend around 1.20 metres and that is not an arbitrary figure.
- Forgetting your model needs 2.4 GHz. Hours spent hunting a fault that is not a fault.
- Not fitting the security screw. A camera you can lift off the wall secures nothing.
- Leaving the detection zones on the factory setting. You get a notification for every passing bike, and at the same time you are filming more of the street than you are allowed to.
- Drilling without checking where your bell wiring and sockets run. Scan the wall, on the inside too.
- Not sealing the cable entry. Water running inwards along the cable is usually only spotted once the plaster starts staining.
Frequently asked questions
Can I connect a video doorbell to my existing 8 volt bell transformer?
With lighter models often yes, with heavier ones no. Plenty of wired video doorbells run on 8 to 24 volts AC, but the Pro models need at least 16 volts. More important still is the power rating: old bell transformers often supply only 4 to 10 VA, and that is too little for a camera with night vision and speech. Check your model’s specifications for the voltage and the VA figure, and replace the transformer if you cannot meet them.
Why does my chime keep ringing after installation?
Because the video doorbell draws a small current continuously and your chime reads that as a bell signal. With a digital chime you solve it with the supplied diode across the chime’s terminals. With a mechanical chime, or if you are not using the chime at all any more, you fit the supplied resistor or power kit. Which goes where varies by brand: follow the manual for your model.
Is my doorbell camera allowed to film the public street?
In principle, no. Data protection rules say your camera should only capture your own home and your own property, and that you must limit filming of the public street and neighbours’ gardens as much as possible, for example with a shield or with privacy masking in the app. If there is a good reason, such as a burglary, it can be allowed temporarily. Keep footage briefly, put up a “CCTV in operation” sign and tell your neighbours.
At what height should I mount a video doorbell?
Around 1.20 metres off the ground. It feels low, but the lens looks upward, and at that height you get both a complete face and a parcel on the step in shot. If your door sits in a recess or the camera faces a wall, use a wedge or angled bracket.
Does a video doorbell work on 5 GHz wi-fi?
Virtually no model does. Video doorbells work on 2.4 GHz, because it reaches further and passes through walls better. If your router uses one network name for 2.4 and 5 GHz, you sometimes have to split them temporarily while pairing. If the signal at the front door is weak, a mesh point or access point in the hall is the answer.
Can I install a video doorbell in a rented home?
For drilling into the wall and altering the installation you need your landlord’s permission. Plenty of housing providers have a camera policy with conditions attached. If you want no hassle at all, a battery model on a mounting plate fixed with adhesive or a clamp system is the least invasive. In a flat you also have the freeholder or owners’ association to deal with, because the façade is shared.
Do I need a subscription with a doorbell camera?
Not always. Without a subscription, most brands still let you view live and receive notifications, but you do not store any footage. If you want to review recordings, you need cloud storage (3 to 12 euros a month) or a model with local storage. Factor five years of subscription costs into your comparison, because a dearer device with local storage often works out cheaper that way.
To finish
The job itself takes half an hour. The homework takes fifteen minutes. And those fifteen minutes are the difference between a doorbell that just does its job for five years, and a doorbell you are fiddling with every month.
Measure your voltage. Count your VA. Check which chime you have. Aim your camera at your own property.
Small tip. Big difference.
Want to master more jobs like this yourself? At Koning van je Woning you will find clear instructions for the jobs in and around your home, so you never have to guess halfway through. Do yourself a favour. Take a look.
Regards from Fred Schouten, DIYer through and through
PS: Before you start drilling, pop next door and tell your neighbours you are putting up a doorbell with a camera and that you are aiming it at your own door. Costs you two minutes. Saves you years of grumbling over the fence.