Installing a Nest Hello Video Doorbell


My doorbell needs to be replaced. The plastic button has cracked and pieces have fallen off, exposing the LED light in the button. It still works but I can tell people are getting afraid to touch it. There’s no real chance of getting shocked from it but they don’t know that. I can’t blame them for knocking.

The obvious solution here is to buy another $2 button like this one at Wallmart. It takes about five minutes to install and you know it’s going to work. But that’s not good enough. We are well into the 21st Century and I just expect more from mundane things like doorbells. I have heard about video doorbells and thought to try one. My neighbor has one. He can tell when UPS has delivered a package and he can scoot home to get it before someone else does.

A video doorbell would be about 100 times more expensive than the simple button but think of the piece of mind knowing who’s at the door – even when you are not home! This is what price deflation does to your thinking – it makes it easy to move up the scale. The $2 doorbell, that I paid $6 dollars for 10 years ago now seems too cheap to even consider. A video doorbell system 10 years ago would have cost thousands of dollars. Now I can have it for $200 or so. I don’t think economists give this psychology enough consideration when they worry about deflation. It makes me want to buy things.

Anyway I looked at a few brands: Ring, Nest, Doorbird and a few others. It’s really a tough decision. I picked the Nest Hello and I’m happy with my choice. But it’s not a five minute installation like the $2 button would have been. It would have been a 15 minute installation if all the stars had aligned.

Analyzing the Current Setup

Both Ring Pro and Nest Hello are designed to work with existing doorbell wiring. Both suggest a 16V 30 VA transformer. Both use WiFi to transfer the video. The Doorbird system is different. It requires CAT5 or CAT6 wiring and uses Power Over Ethernet (POE) to power the unit and ethernet to transfer the video. This is intriguing because it will not soak up the local WiFi bandwidth to transfer video. But it does require that you buy a POE rated network switch. The show stopper for me is the CAT5. There is no way I can snake new CAT5 cable to replace the 18 gauge bell wires. If I was building a new house or remodeling, yes. But I’m not tearing up walls just to replace a doorbell.

My house was built in 1987. In those days they thought a doorbell circuit would be just that and nothing more. Ding Dong, that’s all. No one imagined the circuit would be asked to power a computerized video surveillance system. So the old doorbell is powered by a 10 volt 5 watt transformer. This is enough to power an electro-magnet to slam a rod against a bell. This is not enough for the requirements of a computerized WiFi video doorbell system. So it is reasonable to upgrade the transformer to a more powerful unit.

Over the years they have changed the way that transformers are rated for power. My old transformer is rated in Watts, while the new in Volt-Amps. Both ratings are derived from Watt’s Law: Power = Voltage times Current.  The Watt rating assumes a DC voltage which is constant. The newer VA rating recognizes that an AC voltage fluctuates between positive and negative peaks as a sine wave. So since part of the time the wave is approaching zero, there is no way that an AC power circuit can equal a DC circuit at the same peak voltage. The difference is not great but it is real. Somewhere between 1987 and now the truth police have caught up with those dastardly transformer manufacturers. You can almost imagine the ghost of Thomas Edison railing against Nikola Tesla – He’s cheating you with his Root-Mean-Square gobbledegook.

Anyway, I’m here in the present with a considerably more powerful Nutone 16V 30 VA  transformer that I have to install to make the system work.

Another thing has occurred to me about fitting a sophisticated electronic device into the more primitive doorbell circuit: That bell that goes Ding also goes Dong. When you press the button an electromagnet coil creates a significant magnetic field that drives the rod into one of the bells (the Ding bell). When you let go of the button a second coil energizes and forces a second rod to slam into the Dong bell. Within this circuit, the voltage before the button is pressed is at the rated voltage of the transformer, 10V for my old one and 16V for my new one. When the button is pressed the voltage drops as the electromagnetic field is energized. When released all that energy in the field has to go somewhere so I would guess that the full cycle of press and release causes some pretty wild voltage fluctuations in the circuit. The door bell mechanism probably doesn’t care but a computer based system certainly would. There are two ways to mitigate this: make sure the system has a lot more power than it needs and install devices that dampen wild fluctuations.

That explains why both Nest and Ring provide a whacky looking do-dad that you have to install at the bell mechanism.

Another thing to consider is that my 1987 vintage wires have acquired considerable resistance over the decades. More power is better.

Buying and Installing

I bought the Nest Hello video doorbell from the Nest web site. They suggest a 16V 30 VA transformer but they don’t sell one. I got a Nutone C907 transformer from Amazon. BTW, Amazon does not sell the Nest Hello. If you search for Nest Hello you get other brands of video doorbell (including Ring) in the results and you get Nest’s thermostats in the list but no Nest Hello. It seems petty to me that Amazon does not sell the product that competes with the Ring. Walmart sells them. Home Depot sells them. It’s not like they can halt this train by standing on the tracks. Anyway, I got mine from the Nest site with free shipping.

One thing I didn’t consider is that the 16V 30VA transformer is larger than the 10V 5W one. When my house was built they decided to stick the transformer on the outside of a light box in the furnace room. I’m glad they did that because I can access it easily. But I’m not happy that they placed the light box real close to a metallic heating duct. There is about an inch or two clearance between the duct and the exposed transformer terminals. This clearance would be mostly gone with the new bigger transformer. I don’t want to take the chance of shorting caused by the terminals contacting the duct.

So what can I do?

I could put tape over the duct but that would not be right.

I could relocate the light box but they used this box as a pass through to other fixtures so there are a lot of wires to move. I wish I could rotate the box 90 degrees but it’s not possible without replacing the box.

I could put the transformer on a new box adjacent to the old one, connecting it to the old one with a short piece of Romex/NM wire. That’s what I’ll do. Off to the hardware store…

Ok, so I removed the old transformer from the light fixture and extended the line to a new box from which I hung the new transformer. It is well out of the way from the metal ducting and it has plenty of breathing space should it get hot. At this point I still have the old doorbell installed so I wanted to see if the 16V transformer would work with the old bell mechanism. I flipped the circuit breaker back on and tried the bell. It sounds the same to me. Possibly it is louder but not by a lot.

So now I’m ready to install the Nest Hello. In the brave new world of door bells you don’t get a PDF file that you can analyze and plan your attack. Now you get a video. I watched the video and didn’t take notes. So if I don’t remember the details at minute 12:23, I have to watch it over. But wait – there’s an app!!! Unfortunately like the video, it is a stream of steps that don’t really give you the concept of what you’re doing. Just a step by step tutorial. Turn this screw, click next. Turn that screw, click next.

So I followed the app and got it all together. They do assume that the guy that installed the original doorbell left plenty of slack in the wires so that you could pull out the slack and push it back when done. Not my guy. I can’t pull out any slack. Furthermore, he stripped all the insulation off the wires. That wasn’t a problem back then because the push button housing was all plastic. However the Nest Hello has a nice aluminum case to mount to the doorframe and this is a fine conductor. That means I can’t let any part of the wires touch the casing. Nest does include, thoughtfully, a pair of wire extenders to be used in cases like this.

After getting it all wired up I used the app to add the device to my network. How do you add a device to a WiFi network when that device has no user interface? Which SSID to associate with? What is the password? They have taken a somewhat convoluted technological approach to this problem. They added a bluetooth chip and require a smartphone to be its user interface. After installation, the bluetooth is never used again as far as I can tell.

That would be great if there was a universal bluetooth level that all cell phones had. Unfortunately bluetooth has been adding new features that have been rolling out for years. New device makers alway assume that everyone keeps up to date with these rollouts. Not me. I have a vintage Samsung S5 that generally serves me well. Except when trying to install a Nest Hello. The two devices cannot agree on how to make a bluetooth connection.

So I use my wife’s Apple 6S. It connects readily and I’m on my way (fumbling with WiFi passwords on a mobile keyboard). It’s done. I can see a live video of my front porch. I show my wife and she says “go out on the porch so I can see you”. I go out and she manages to take a screen shot of me just as I sneeze. What have I wrought?

One Reply to “Installing a Nest Hello Video Doorbell”

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