The Nest Hello video doorbell was designed in North America, which is why they were built to run on 12-24V AC, the problem is you cannot buy a wall mounted doorbell chime in the UK that has more than 8V.
This is why you'll need an uprated transformer, they range in cost from £5 to £30, our advice is don't skimp on this component as the cheap ones get hot, quite often buzz loudly and have a short life span - expect to pay between £15 and £25 for a reliable device that'll run cool and last a good few years.
You've set everything up perfectly, followed the instructions to the letter and your doorbell is working and connected to the app but when the button is pressed the chime doesn't 'ding dong'?
Something that can cause a problem is the bell wire and excess length is known to have a detrimental effect on performance.
That bell wire used to connect the doorbell to chime and transformer is very thin, especially so in new-build houses.
This creates a problem when you try to pass 10VA down lengths greater than 3 metres, bell wire is a very effective resistor, so if your chime is 4-5m from the Nest Hello that may be the reason the chime isn't activating.
The white disc that comes with your Nest Hello doorbell is essential if you want to have a wall chime as part of the system then you're going to need it.
That little disc is full of very delicate micro components so definitely don't wire it into the 240 mains voltage side of the circuit as you'll overload it.
What does it do? It provides the perfect amount of power as a permanent live feed to your video doorbell, when someone presses the button it releases power to the chime so that it can activate.
You love your Nest Hello but why does it generate so many alerts?
Finding the perfect level between relevant and annoying takes time but this is why the functionality you get from Nest Aware justifies the additional monthly cost, especially the 'Activity Zone' feature.
Unlocking activity zones is how you define which areas you want notifications from but they aren't 100% accurate, think more like 80% and position the boundaries a little more conservatively.
Overlap zones of varying sensitivity and you'll get the coverage you want without the annoying never ending lists of alerts just because you happen to live on a main road with a footpath by your front door.
Conventional wisdom says that you should install your new video doorbell on the same side your door opens however what if your existing push button doorbell is the opposite side?
The reason this was done is usually one of convenience because the closest power source was on that side of the door.
Any good electrician can re-route the wire around your door but it will definitely involve an hour or two more labour and redecoration.
Our customers experience has shown that visitors and delivery people press the button and stand back to await an open door, that's just what normal people do so don't overthink it!