Lets start here. Wifi devices are wifi devices.
The magic that makes WiFi6 better for IoT is thr fact that THE ROUTER handles a ton of low bandwidth highly chatty devices better. Thats the secret sauce. Get a good router that supports AX.
So you won’t find ‘new devices’
If you want WiFi devices (Personally o do not) WiFi6 is absolutely the way to go, but you wont find specific devices.
I really enjoyed reading this thread. It reminded me of the discussions (religious wars?) programmers have about the best programming language… 
I know the OP is Zigbee vs Z-Wave vs WiFi, and I have my opinions and lessons learned from experience including many decades in industrial automation. But, if I was to do it all over again from scratch (new home construction with a nice budget), I would go all wired as much as possible (Ethernet interfaced DIN rail based controllers, relays, etc.). It’s secure, local, reliable, and fast.
P.S. I’ve never seen Zigbee or Z-Wave used in industrial automation but I have seen WiFi used on secured VLANs.
Me too and I’m the OP!
This has been a fantastic thread to follow… Tossing my hat into the ring, I believe all three of them have strengths and weaknesses, and a good, stable HA system should make use of them.
Operating in the 900MHZ band, Z-Wave is great for longer distances with fewer repeating devices. It is ideal for switches and dimmers, along with outdoor sensors and other devices that are far from the core coverage of the mesh. It’s not so good for chatty devices, especially those which report power usage. This can raise havoc on a mesh. Since migrating all powered devices to Z-Wave Plus, everything has been stable and reliable. (I have 72 devices using Z-Wave JS)
Zigbee is excellent for large networks, especially those with lots of sensors (motion, contact, etc). It also handles chatty energy reporting devices very well too. With a good coordinator and the right configuration, Zigbee scales well in to the hundreds of devices, even in HA. (I currently have 214 using ZHA)
WiFi is good for powered devices, such as plugs that report energy, and specialty stuff like ESP32, equipment integrations, cloud stuff, etc. In my experience, it’s terrible for use with battery powered devices, motion sensors, etc. I just use it to connect various systems like UPS’s along with a handful of Kasa devices I got very cheaply.
In my experience, multi-mesh deployments, especially large ones tend to offer better performance. A common design pattern I use is to use a device on one mesh to trigger a device on another. For example, a Zigbee motion sensor to trigger a Z-Wave light switch. This gives a near-simultaneous response of the switch before LED is still lit on motion sensor even goes out.
It’s also a great boost to WAF. Something that was sorely lacking before I migrated from Hubitat a year ago.
That’s why I’m looking at Zigbee as an addition to my Insteon/Z-Wave/Wifi setup, right now if I want to update sensors I have to poll it since ZwaveJS doesn’t do it regularly so my best chance to not blast my Z-Wave network is to do a multicast call on a group, meaning I have to keep that group updated as I add sensors.
Maintenance is a consideration as well. Devices will die and you need to keep at least some spares around for when this happens. I have z-wave(89 devices both wired and battery) and wifi (shelly). The more wired z-wave devices I added the more reliable the network became. About 60% wired devices. I love shelly devices. Inexpensive and versatile. N-way switches are their one limitation. My n-way switches are all z-wave.
If you run Z-wave, IMHO, you should run surge protection at all panels and sub-panels. My stability and death rate of devices went down significantly after whole house and in-house surge protection installed. I like siemans for main panel and Intermatic for sub-panels. The Intermatics’ have replaceable surge elements. Surge protection is important for all IoT and your major appliances.
Something more to think about as you build out your system.
Happy Holidays Everyone!
I always keep spares around for every type of protocol I use. I had a half dozen spare Insteon (I’m phasing it out so as they die I’m not restocking spares), a half dozen Z-Wave and a few Fibaro Z-Wave motion sensors (even though none have ever died on me).
I’ve never had issues with Z-Wave dying really, but the Insteon was super sensitive to power outages and power surges and after about 10 years I would lose at least one device each time it happened (hence phasing them out). This sort of makes sense since the bulk of the Insteon network is carried over the power lines.
The biggest problem for me, regarding Z-Wave, isn’t the technology, it’s the manufacturer. I’ve even been switching that out recently to standardize all Z-Wave wired with Inovelli stuff because they are one of the only Z-Wave manufacturers I found who actively update firmware. The cheap Chinese stuff and anything GE has always given me headaches and never get updated. My current go-to’s for reliability and features is Inovelli for wired and Fibaro for wireless.
Is it really all about the access point? Maybe that is my misconception but as far as I could understand it, a wifi device will not benefit from AX as long as it does itself not support the power saving techniques.
Or will my 5 year old ESP use less energy if I use an AX access point?
No it wont benefit from the energy savings but the bandwidth issues and traffic ossues are mostly taken care of. (the paft that hammers yiur internal network.)
Yes individual devices benefit of they’re doing AX, but the biggest benefit is on the backend - preventing all those tasmota switches from saturating your network and making it unusable.
Hardwired. - But, like telephones, even though it’s the most reliable, it’s a pain in the butt.
So I started with all three (Z-Wave, Zigbee, Wifi) and have recently noticed that I have ended up with almost exclusively Zigbee, except for all my Alexa stuff which is all wifi. It wasn’t really intentional… maybe it was just in the background regarding lower cost, more product availability, and in my environment of a suburban lot with neighbors near but not real close… it just ended up that way.
I use a mix of Wifi devices, Zigbee and Z-Wave.
I try to avoid wifi devices, my AP’s and network can handle it but I prefer to use the wifi bandwith for my own devices, not smarthome sensors. They are also often badly implemented, never updated and unsafe. I counter that with a seperate VLAN but not everyone has that possibility.
I have been using Zigbee mostly with Aqara sensors, blinds and some sockets and lights. I use it via Zigbee2MQTT at the moment and encounter not a lot of issues, the only issue I have is that a few temperature sensors stop sending status updates. It’s a known issue with Aqara sensors and I haven’t been able to fix that yet. I am thinking about migrating to ZHA but I’m not sure if all my stuff will work with it.
Z-Wave for me has been proven the most stable yet. Right at the beginning I had a few small issues (years ago), but that was mostly due to not knowing the technology that good yet and being a noob. I am still using the old implementation and it’s been stable for years. I am planning to migrate to Zwave-JS, however with 400+ entities I have no clue how long this will take me and that is what is currently keeping me.
So for me: Z-wave > Zigbee > Wifi
Zigbee is rock solid and has great range. My installation is about 200 m from end-to-end including the yard, and it would be quite difficult or expensive to do with wifi. Two stretches are 40m and 30 m, and the longest one is 80 m (with some Fresnel-zone interference) between zigbee devices.
That said, I have som Shelly S which use wifi, which are excellent products, perhaps the best switches on the market and will get more Shelly products. I see no problem using wifi in the house, and it hasn’t interfered with wifi so far, but OTOH I use Unifis professional products for the wifi. But still, there are places in the house with bad wifi reception, but never any problems with Zigbee.
Also, great batterylife on Zigbee, for example the Philips Hue Motion detectors which have lasted for over a year on common AA batteries even outdoors and in freezing temperatures.
As several have said - don’t use wifi for battery powered devices.
Keep in mind the “Matter” is the replacement for Zigbee not Z-Wave. So dont bank on the Z-Wave getting updated. Remember that:
“Matter (formerly Project Connected Home over IP, or Project CHIP) is a new Working Group within the Connectivity Standards Alliance (CSA, formerly Zigbee Alliance).”
Now if and when this comes about I am all in. As far as WiFi devices and even Tuya. I have about 150+ (2.4Ghz) WiFi Devices, including Tuya, Shelly, ESPHome, WLED, and Broadcom based Mini-Split HVAC units. I am using LocalTuya and everything works locally. I also have (5Ghz) 6 FireStick4Ks and 8 Echo Devices which obviously do not work locally but give me voice control.
Now I do have point out that I am using UniFi APs and had to add a second AP to split the WiFi load. I have a separate SSID for all the IOT Devices. Also I am just a bit more knowledgeable about my setup than most average people. So for some ZigBee might be better if you dont know how to properly setup your WiFi networks.
With something like UniFi I could if I wanted to have a dedicated WiFi-AP and even assign these devices to their own Subnet with no access to the rest of the network. I digress that most people would not be in a position to do this.
If and when Matter is ratified I will probably give it a try. As of now I will not be jumping on the ZigBee bandwagon simply because until Matter is ratified and out in the wild there is no telling what devices will get firmware updates to use Matter and what will not.
Short of it is that in my opinion WiFi is a perfectly viable option as long as your smart about your setup. As with anything else you need to plan not just jump off the deep end.
LOL. Being a Control Technician / Engineer myself I have to agree. I have only seen ZigBee in use with Commercial / Industrial Automation a couple times, and never used to actively “turn thing on and off”. Meaning I have never seen a ZigBee relay in use. Only for sensors to get basic data (Temp, Hum, Vibration, Lumens, Etc…). I have however, seen tons of WiFi and Ethernet RESTful API relays. We don’t use them on our Campus as all of our stuff if either BACnet or MODBUS.
Honestly I think the only answer that will work longer term if for the Industrial / Commercial guy to start working with the Home Automation guys. So they can come up with a true open standard, kind of like BACnet was meant to be for EMS/BAS systems. BACnet can exist on just about any media type RS232, RS485, WiFi, and Ethernet. I have even seen BACnet over ZigBee but I digress that was some kind of proprietary ZigBee to BACnet HUB so I can really say what was happening on the ZigBee side. I have even seen MQTT to BACnet hubs.
Its an exciting world we live in, and I for one cant wait to see where all this goes.
I have a quick question about Matter, which I understand the answer could be a “we don’t know yet”:
Or did I just missed the mark by a mile?
Short stupidly oversimplified version… Matter allows one basically encapsulate other home automation tech such as Zigbee inside IP. Its one of the many reasons for its potential.
So… technically it would not be impossible for “Matter over z-wave” being a thing, correct?
(It’s just less possible than, say, zigbee, I know.)
(Or did I just missed the mark again?)
I would not say that its impossible that “Matter over Z-Wave” to happen. Just unlikely for two reasons. It is the ZigBee working group that is writing Matter, and Z-Wave have strict rules on Z-Wave certification. The second reason is why there are less Z-Wave devices on the market and why they cost more.
They do list out the different Protocols supported. So there will be Matter over WiFi and Ethernet, as well as IPv6 over BLE, and BLE Standard. Notice the 802.15.4 (ZigBee) and Thread but no Z-Wave on the list.
I really do like the idea of Matter but unless they release like tomorrow they will be late to the game. Without knowing how many manufactures are going to release firmware update for matter it makes it hard to plan for it in the future. Shelly could for instance decide to release Matter over WiFi firmware rather than the CoAP & MQTT they offer now, but only a handful of companies have said they will support it fully.
Like Amazon, Google, Apple, and Samsung has said they will, but since they are fully cloud based we don’t know what this really means. And honestly they are only useful for the voice integration. None of the aforementioned system give any true useful amount of automation logic. Which is why we use Home Assistant anyway.
I started with Z-Wave… Expensive, long range, slow, and it just works, great for powered thermostats, out buildings, and for “large” houses. Added some Wifi plug sockets, and wall switches (Turn your head and spit) TUYA. Lastly added some IKEA Zigbee devices.
I am least impressed with Zigbee. Everything has a different way of pairing and each manufacture has its own flavor of Zigbee. Zigbee will work great if you buy all your stuff from one manufacture, use their hub and integrate that in HA. I have tried Zigbee on a Sonoff 3.0 stick and a HUSBZB stick and it was flaky with ongoing battery and range problems.
I suffered through all of the TUYA outages and nonsense too… But with wifi outages within a day or two of the problem people have developed and implemented work arounds and solutions. My battery problems with IKEA Zigbee devices has been a 8 month (still unresolved) slog.
My #1 rule would be avoid Zigbee from more than one manufacture… But I NEVER make sweeping generalized statements like that.
As for Matter… LOL don’t hold your breath. The same motivation that has Zigbee device manufactures mess with the “standard” so you can only buy their devices isn’t going to be solved by the same companies who caused this problem in the first place. Lets all get together and come up with an interoperability standard… Ya that was the promise of Zigbee.
I started with Fibaro and have mostly z-wave devices. Around 40 wired devices and around 50 wireless. Speed is still okay, but I hate changing the batteries. Probably €50 in batteries per year.
I have a Fibaro HC2 central in the house and use it now as a very expensive z-wave hub 
Besides z-wave I have around 20 shelly devices and also a few esphone wifi devices.
I am slowly migrating to esphome over ethernet, powered by POE. Are there more people who do that? I think that is the best way to go.