THIRD PARTY PROTOCOLS AND DEVICE MAXIMUMS IN HOME AUTOMATION
Zwave has a hard limit of 232 devices per network (for exactly the FF reason you suggest, they reserve some addresses for internal networking stuff) . The new series 700 SOC (“Zwave Plus V2”) Will eventually increase that, but right now there are no smartthings hubs that have that chip, And in fact very few from anyone. And I’m not sure the number of devices has been increased yet anyway, that’s actually a second iteration. You’ll see quite a few Zwave hubs that set an artificial maximum of 150 just because it’s easy to remember.
But smartthings is a multi protocol platform. And zigbee allows for thousands of devices on a single network, which is why it was so popular for commercial Sensornets.
Then we come back to Wi-Fi. Many residential routers have a limit of 32 devices. The more expensive ones tend to allow for more, but you will very likely hit a limit somewhere between 100 and 150. There’s almost always a hard limit of 250, and if you actually run your network with traffic for all of those you may find that your router overheats. (Really.)
Eero is often called out as being suitable for Wi-Fi power users, one reason Amazon bought them.
One eero can support up to 128 devices (you read that right). That’s one very connected home. However, if those devices are heavily using the Internet for activities like streaming video, you’ll probably see best results using up to 30 devices with each eero.
Where a lot of home automation networks, regardless of protocol, run into problems is when they start adding virtual devices. Especially if they are using them to equate to modes or groups or scene filters. I’ve seen set ups with 25 physical devices and over 100 virtual devices for these kinds of reasons.
(Homekit, by the way, has a limit of 1000 devices per account, although there are some shared memory issues which means you can see degradation earlier than that.)
IMPLICATIONS FOR SMARTTHINGS
So where does that leave us?
If you had an all Zigbee network, with a lot of sensors and some virtual devices, you could definitely hit 300 or 400 in a typical single-family home.
If you have an all zwave network, you won’t get anywhere near that. You’ll probably hit practical limitations between 100 and 150. And some Samsung support people tell smartthings customers problems can occur when you have over 40–I’m not sure where that advice comes from.
For years, smartthings staff have said their typical customer has 15 or fewer devices and doesn’t run any custom code (which means no virtual Devices). That would match nicely to an all Wi-Fi set up in a typical home, or maybe all Wi-Fi plus a hue bridge or another zigbee/Wi-Fi Bridge.
And smartthings just announced they are getting out of the IOT hardware business, which I would guess (I don’t have any data to support this, it’s just a guess) that they are assuming that most of their customers are going to be in a “hub optional“ configuration, which likely means Wi-Fi devices.
An Update Regarding our Hardware
So…no question, a power user With at least one hub who is using zigbee devices and virtual devices could go way over 200. (That’s why I tagged @johnconstantelo .)
A power user with at least one hub using Z wave plus and virtual devices might squeak over 200, but is more likely to be just under.
But your typical smartthings customer isn’t even going to reach 50 devices. Even with some virtuals.
THE FUTURE IS: LESS?
All of which means: not Luddites. Rather, future oriented, to where many many people have a little bit of home automation, But most have no home automation hub. They are focusing on a different market niche these days.
I’m not saying I like the device limit, and I don’t like that it’s not well documented and the changes are often not announced. . And I much prefer the homekit approach of picking a genuinely large maximum even for a fairly simple system. But I think I understand why somebody designing a UI for the expected customerbase might think 200 was a generous number. I don’t agree with them, but I understand how they could get there.