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I have ~65 Z-Wave devices around my house, and I definitely notice lag from time to time. Recent versions of Z-Wave seem to be significantly faster and I've noticed it less.

I can't say I _love_ dealing with Z-Wave. But I do like having a single protocol throughout my house. At the very least, any issues I have tend to be consistent. I'd say in this past 6-months, I've practically had zero problems. I blame that overall improvement on ZwaveJs, because some of these devices are at least 5 years old and they're just cranking away without issue right along side my more recent Zooz and Inovelli devices.

That said, I've been strongly considering multiple Z-wave hubs, each running zwave2mqtt with a central mqtt server just to keep everything as fast as possible.

The single protocol throughout my house was my primary goal too, just to reduce complexity of having to deal with multiple hubs and integrations... but with my new house I did away with that.

Lutron Caseta for physical in-wall switches, IKEA Tradfri for cheap motion sensors/lighs, Philips Hue for more expensive motion sensors/lights, and a whole slew of Thread enabled devices, all controlled from HomeKit.

I don't really notice that its a bunch of different protocols/wireless standards underneath. I can control it from a single location which also makes it easier for guests/people visiting. Hand them an iPad with the Home app and they can control the house, or add them a Guest to my home on their own iOS devices.

I do miss some of the more advanced Home Assistant stuff I was doing, but overall the experience has been much cleaner, and with almost 0 lag.

Sounds like you had some non-zwave+ devices or you were using a lot of s0 encryption. Both are known to slow down the network. Like everything it’s gotten better over time. The 700 series stuff is pretty quick.

Encryption was insanely slow when I first tried it on my Inovelli Red Series switches. Without encryption it was an instant (feeling) response time.

I'm also running a Zwave network and it's highly responsive with around 50 devices. A friend of mine is running a few hundred devices and I haven't heard him complain much about it, all of his actions/triggers/etc seem to execute pretty much instantly. I'm going to guess that his network topology has a lot devices that are only accessible by repeaters, or aren't using Zwave+. Zwave is pretty much _the standard_ for large professional smart home installations and scales pretty well if implemented properly.

Yeah, I used virtually all Z-Wave switches and dimmers in our new house (and motion sensors, temp sensors, etc) and haven't had an issue. The one time things seemed a bit laggy I had to "optimize" the network, which I realized I had NEVER done until that point. All issues went away.

We have well over 100 Z-Wave devices spread over 4000 sqft.

That's less devices over a larger area than I had.

My house was 1200 sq ft, with a little over 200 devices.

What does optimize mean in this case?

The Z-Wave network, while being a mesh network, is not a dynamic mesh. Nodes follow a precomputed path from themselves to the controller (with backup paths -- it's based on a node having a predefined list of adjacencies). You need to regularly poll each node in the system and determine it's optimal path from controller->node and node->controller and redefine it's adjacency list.

This process is entirely automated but does take some time. It's absolutely critical to do this when adding a new device (both for the new device, as well as the overall network) but I found that just doing it regularly works great. I have all my networks configured to do this at 4AM daily since the network is unusable for the few minutes it takes.

All the devices were Z-Wave+, it was the one thing I was buying for. Not all of them supported the new encryption standard which started rolling out after I deployed most of my switches.

This was in a ~1400 sq ft house, with a little over 200 devices (motion sensors/lights/switches/smart plugs/humidity sensors/weather sensors). The network had a few repeaters the longest hop was 2 hops from the controller to the end device.

> humidity sensors/weather sensors/motion sensors

This was your problem. I've been using Z-Wave in my house since, I think, around 2010. I had major major issues with it at first exactly like what you describe. I "fixed" them by doing two things.

A) Banished all battery powered devices from the network. Seriously. I have one in a hall closest I haven't gotten around to getting rid of, yet. The network seems fine-ish with only that sensor but large volumes of battery powered mostly asleep devices, it falls over.

B) Abolished any notion of using my Z-Wave network for sensor reporting. No tracking humidity or weather or power with my Z-Wave network because, as you mention, the Z-Wave network completely falls over when you have volumes of sensor traffic on it.

Want to have one humidity sensor which reports hourly? Sure that's fine.

Want to have a humidity sensor in every room which reports every time there is a 1% change in humidity? lol no, your network will fall over.

My Z-Wave networks are quite large at this point, 200-300 devices, and consist of Jasco/GE switches, Jasco/GE fan controls, Jasco/GE smart outlets.

Removing sensor traffic and battery powered devices from my Z-Wave network has made it extremely reliable for me. Unscientifically I would say 99% of Z-Wave control commands execute in <1s.

Jasco/GE switches is what I used throughout my house... but the whole point to me was to have a smart home.

So when humidity goes up in the bathroom, the controller would kick on the exhaust fan.

When temperature drops in a room that is active below a set point, the fan is kicked on for the forced air to start circulating + heat would get kicked on if necessary.

The whole point of having a smart home is to have a smart home that does stuff for you. Walking into a room and having lights turn on is the best thing EVER. I don't want to touch a switch if I can avoid it.

If sensor traffic is not meant to go on a Z-Wave network then they shouldn't allow those device classes to exist on the Z-Wave network.

On the sensors I had I cranked up the change required before it would report, but it also did periodic reports. I had to also update those so that the network wouldn't get flooded.

Sleepy devices/battery powered devices on the Z-Wave network for things like window sensors/door sensors is kind of the norm. It's hard to run power for all those things, and those sorts of security sensors are handy for not just automation but also for peace of mind!

The thing is that I have a similar setup now with Zigbee/Thread devices... and everything just works. In fact due to not having motion sensors that also act as humidity/temperature/light sensors I end up having more sensors on the network, yet it is far more stable.

I'm not arguing for/against z-wave, just, pointing out the flaws in Z-wave and how I overcame them.

I also have things like humidity -> fan, I just do other things for the sensor network.

I was an early adopter for sure. This was back in 2016ish when I installed all of the devices. All of the devices were Z-Wave+ (specifically bought for that) but many of them did not support the newer encryption, and it ended up being a mixed network of devices for sure. Only the last few devices I bought supported the new encryption standard that was being rolled out at the time. I ended up getting a new Z-Wave hub that supported it to be able to securely enroll my new devices... but all it did was destabilize the network further.

It just left a horrible taste in my mouth, and once bitten, twice shy is definitely the case here.

The other thing that made things slow was sleepy devices that would wake up to report status. Things like motion sensors that also reported humidity, light levels, temperature and more (I do wish I could find a sensor like that for Zigbee/Thread... the multiple things in one was kinda nice). Every time they would wake up to report it would flood the network with traffic. And with each additional sensor I would have to tweak how often that would happen (and thus how accurate the data was over time) to reduce the amount of chatter on the network.

Ok yeah I only have 16 devices but I have 188 entities - I haven’t had any issues with sensors except with a power mains reader that didn’t support zwave+. After I removed that everything has been great. I also have a Zigbee network of about the same size which has also been pretty solid. One tip I didn’t know about at first is that you should have your transceiver plugged in to a usb extension cord and not directly into your pi/whatever.

What you described is exactly why I'm waiting to install more automation in my home. I think Matter + Homekit (assuming Apple continues to work on Homekit as it's still pretty clunky for me UX-wise) will eventually be the solution for me as I'm already so deep in that Apple ecosystem.

If you've watched Linus Tech Tips videos recently, there's hours of content covering his Z-Wave woes. It's funny, his house is supposed to be automated but it ends up eating significantly more of his time in debugging than a manual house would.

If you have good wifi, you don't need to wait. I have a two story house and the floor plan looks like a T-shape, so I basically have 6 different zones. I pulled Cat6 everywhere for decent AP coverage. Right now I have about 80 Meross light switches and dimmers, 6 wifi blinds, wifi garage openers, Ecobee thermostats, multiple Apple TVs, ton of personal devices - easily over 200 devices on the LAN, most of them connected to HomeAssistant. Instant status updates with no problems except for the occasional need to reboot a wall switch due to power issues. Meross has a tiny hidden button at the bottom of each switch that instantly reboots the switch.

I bought Meross products off Amazon in bulk and absolutely love them. I have single pole switches, 3 way switches, single pole dimmers, 3 way dimmers, and a few smart plugs, power strips, and RGB bulbs.

PS: I even have a few Z-Wave devices and bought Zooz Hub ZST10-700 to work with HomeAssistant. I use these to measure power consumption on a garage freezer and a space heater. As long as the Z-Wave devices are close to the hub, there's no issue. But oddly enough they sometimes send negative power usage data which HA complains about.

The funniest part is he have to use two smart thermostat in each room and he realize that one smart thermostat heat up the other one and fucked up the temperature reading.

I have about 40 Zigbee devices connected to Zigbee2mqtt. Everything has worked since I started 3 years ago. Its only gone wrong when I mess an upgrade up (once).

I like that my smart home is not a full time job. It's nice being set it and forget it. Heck I've spent more weekends stopping Windows breaking my NVR recording system then Zigbee. It's great.

I'm on my second home of full Z-wave (mostly Fibaro, pricey but would recommend) and though smaller this isn't my experience at all.

No it's not perfect but agree with others that the S2 seems to be way better.

Also bandwidth as a metric to aim for seems like a bad choice for IoT to me.

What smart light switches would you recommend?

What was the problem you solved with Z-Wave?

Agreed! Messes with Wifi too.

Z-Wave runs on 900MHz which is plenty far away from any commonly used WiFi bands.

Did you consider separate VLANs for each type of Z-Wave hardware to reduce the broadcasts?

The problem isn't the network, it's the number of devices.

My (likely incorrect) assumption has been that my zwave stick is handling everything serially and falls behind when traffic spikes.

It's not that the Z-Wave stick falls behind, when a Z-Wave device is broadcasting everything else has to go quiet (nature of RF), but the transmission speed is just very low, so when chatty devices (think sensors that report multiple bits of information such as humidity, temperature, light level, UV level, and more) are sending data you can't also turn on a light.

When you have a lot of those devices on the Z-Wave network (multiple motion sensors in a room to do more accurate presence detection and the like) those chatty devices slow down the network tremendously.

As the other commenter said it's not a LAN issue. Z-Wave is a mesh radio protocol totally independent of the LAN. There are in fact issues with older Z-Wave specs and versions bogging down due to congestion.

Ok my bad. It's a L1 or physical layer issue.

Zwave talks on 800-900MhZ and doesn't share medium with ethernet frames, so there isn't a concept of VLANs. Each Device meshes with anything and everything in its immediate broadcast range to provide some elasticity to the network. I can imagine at some high point of devices that the medium could become saturated