I'm new to HE ... coming from ST. I've connected HubConnect to my old ST for some testing while I migrate and I was wondering if there are any drawbacks to running multiple HE hubs in my house + HubConnect ... since we have a pretty large house.
We're mostly using Inovelli Red Series Dimmers + Graber Shades.
Welcome. There are several here that have it set up that way from what I've read, and I've never seen anyone that regretted it. If you have a big enough house, frankly it might be the only way to get good coverage.
The main drawbacks, as I see it, would be that you have two hubs to manage, two networks (Z-Wave/Zigbee) to worry about, and the need to "mirror" devices between the two.
The first issue isn't really that big of a deal (hub "management" is pretty easy--modify apps/devices or update hub firmware when you need to but otherwise set it and forget it). The second likely isn't either in your case (with a large house you'll probably have lots of devices, including repeaters, to make a strong network for both hubs).
That leaves just the third thing. You have to choose a device on its "real" hub to share to the "second" hub. (May sound obvious, but there isn't anything automatic that will just share all devices.) If you rename or swap out devices on the "real" hub, you'll then also have to deal with that on the "second" hub. Again, not necessarily a problem--just how sharing devices like this works.
Hubitat staff have teased an upcoming feature called "Hub Mesh" that is a bit easier to set up compared to HubConnect (everything is already built-in, plus name changes and device status are synced; for HubConnect, you must manually install/update the apps and either manually install/update the drivers or use something like Hubitat Package Manager to automate it; the apps are not under an open license--but support is certainly fantastic, and I'm not recommending against it). If you can wait for the next hub firmware release, 2.2.4, this should be in that. HubConnect will work now (and continue to work then), and it gives you a bit more flexibility that you may or may not need (sharing to a cloud hub beyond just a local hub, SmartThings integration, etc.).
But before you go down this path at all: do you need to? Since you mentioned house size, my guess is that you are anticipating range issues. Z-Wave and Zigbee are both mesh networks, where repeaters/routers (generally any mains- or USB-powered device of that protocol on that hub/network) will repeat for other devices, effectively extending the range of your network. There are some limitations: Z-Wave is limited to four intermediate hops, and Hubitat's docs suggest the max distance with that range is about 600 ft or 200 m from the hub. Zigbee doesn't have a hard limit on hops but in most cases can't go quite as far between devices per hop. But in either case, with a centrally-located hub, you might be good-to-go without worrying about any of this. Or not--and in that case something like you're planning may be a good idea. And it's certainly one you can try regardless.
Thanks for the feedback. I've had range issues with ST ... but I actually think it was just ST sucking. I'm already seeing better range with HE and quicker device joins and responses. (like instant vs. ST taking forever to find a new device if at all). I'm just trying to get ahead of potential issues. The fact that HE also needs an ethernet connection limits where I would place the hub since I don't want to throw into my equipment room since there is a ton of interference and steel racks ... we actually have a lot of steel/metal in the house in spaces that almost shield an entire area.
I picked up an IO Gear Ethernet2 Wifi adapter that everyone seems to love, but I don't think that's working for me since I have a separate router and many WAPs. Their documentation eludes to the device being meant to work with a WiFi Router (vs. WAPS + Separate Router) ... and I'm experiencing issues that lead me believe that the IO gear one won't work (maybe another will).
All of this is moot if I can drop 2 hubs. The mirroring seems to work pretty well between the HE and ST. I think I'll just start with one HE ... and add devices out and see if I'm in better shape and if I run into range/hop issues, I'll add a 2nd HE hub.
You may want to look into powering the HE hub via POE, many do that and it can make it much easier to only have to run ethernet to the location where you'd like the hub.
For multiple HE hubs, you'll definitely want to see/try the new Hub Mesh feature that is coming on 2.2.4 before using Hub Connect. For sharing w/ST hubs HubConnect is the only option, and some do that to keep using ST Nest integrations that aren't fully supported on HE.
When is 2.2.4 coming?
When it's done... No release dates are given.
Oh and I'll definitely need ST integration since I have Brilliant controls throughout the house and HE doesn't work with them yet. I can mirror the devices I need into ST and then use Brilliant/ST integration to operate. Basically using HE as the brains, but ST/Brilliant as my UI for controls.
As noted by Joel. It's in beta now, but predicting when it will finish beta is like predicting when I'll get to the garage clean-up I've been promising my wife. There is no firm date. 
Hopefully 2.2.4 will drop this month, but if we get into December and and it's not out, I never said that. 
Yeah, so you can set up HubConnect now for what you want to keep running from ST, and use Hub Mesh later if you add the second hub...
i was wondering about the multipe zwave and zigbee radios competing with each other and zigbee with wifi.. Any comments?
Keep distinct zigbee meshes on different channels from each other, and on a channel that doesn't overlap with whatever wifi channels you are using. Zwave you don't have that option, but I have used up to 5 separate zwave meshes at the same time with no major issues.
ya i was sowrried about that.. i already dont have any free wifi ranges.. between my neighbors and both 5 and 2.4ghz and an extender that uses separate wifi so not to 1/2 the throughput..
Then the best you can do is pick in-between zigbee channels - 15, 20, 25 - and hope the interference isn't too bad.
(I left off 26 on purpose - it is a weird ■■■ channel, and many devices have a low pass filter on the high side which can chop off some of it frequency)
my main 2.4 wifi is on channel 2.. guess 2.4 extender is on the same channel..
weird because the 5gz is not. zigbee is on channel 20, no guest wifi networks enabled..
for reference even though it doesnt conflict 5 ghz is on 36 and 42 and extender is on 149(p) + 153 + 157 + 161
secondary 5ghz in garge only for tesla is on 52 and 54
i have the 2.4gz band reserved for g only.. n and ac is only currently on 5ghz
here is one that shows all 2.4gz channels not just 1 6 etc.
You mean there are people that use channels other than 1, 6, 11?
you answered the zigbee channel interfernece.. i knew i could separate those, but what about people with multiple hubs and the multiple zwave meshes on the same frequency .. don't they cause interference.. has anyone actually studied it and looked at signal strength changes etc.?
or are most people with multiple hus disabling one of the zwave radios and just using hub connect etc?
unless you illegaly get a euro hub and euro devices and run it in your house? lower freq. should have slight better range lol
Yup, you could go rogue and get a frequency not designed for your country. I wouldn't endorse or recommend that though.
In practice, I never have less than 3 zwave networks going at a time. Never had issues with interference. Not saying it couldn't happen, just relaying my experience.
Download the Hubitat app
