I'm curious to know if more than one hub are required in my house to control all devices. I currently have the Wink system and have (2) Wink hubs that cover different devices based on their locations. Does the Hubitat work in the same manner or is one hub sufficient for any size home?
Unless you have a lot of repeaters, you may want to look at multiple hubs depending on construction and physical layout.
Required, no.
I have 3 hubs covering my Home... Upstairs and downstairs. But I could just as easily split my home Left/Right, North/South, or diagonally 
I split it for resiliency reasons.. I didn't want to lose the whole house if one hub croaks. Can you put all eggs in one basket (hub)? Yes. I personally just don't want to. No requirement beyond my own brain. 
Thank you for the response. Being new to Hubitat I'm not sure if I'm asking the question correctly but are you able to integrate or control all devices from all (3) of your hubs in one location or main dashboard? I'm comparing this idea to my Wink system where my upstairs and downstairs hub devices are all in the one wink app.
Using Hub Mesh, yes, all of your devices can be controlled from one hub, therefore one dashboard. No matter how many hubs you have.
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Hey there, for me, 2700 sq ft house, 1 story, 1 hub. Mix of zigbee, z-wave and z-wave+, no issues with my mesh
Good luck and enjoy
Unfortunately the only answer anyone else can give with any certainty is...
It depends.
On whether you have zigbee or z-wave devices and the number of repeating devices for each protocol.
On not just the size of your house but also the physical layout, what your walls are made of, what’s inside the walls, and other potential sources of interference with propagation of the wireless signals, which could mean physical obstructions in the home or competing radio signals (in general more of a potential concern with zigbee than z-wave, since it’s in the same frequency range as 2.4GHz WiFi networks).
And on other factors specific to your home and how you intend to use the hub.
It’s tempting to make conclusions from others’ experiences, and you can consider adding some details to what you’ve shared so far re: your home and devices to get some more input, but just realize that YMMV no matter what we’re able to share here.
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One hub can do it, you just need to build a good mesh. I came from Wink when its collapse started, so I can tell you what I found. Wink’s antennas seem to have greater gain than Hubitat’s. I just shrugged my shoulders and bought a bunch of repeaters to build a strong mesh. I would recommend Ring Extender V2 devices (I have 5) - they have built-in battery backup and can keep your mesh up to locks and door/window contact sensors during power loss. They are a bit tricky to pair, post in the forum if you have difficulties; they seem to need to be paired S2 in order to report power fail events.
Welcome to the Hubitat community.
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Totally agree, my home is small, two story, a shed, and a seperate two story outbuilding. SmartThings Hub covered it ok, locks were a problem. C7 has trouble. I have a hub in the two story building, two hubs on my first floor and another on the way for the downstairs. The C7 zwave antenna seems to be much less robust than Smartthings, Walls seem to have an oversized negative impact, especially if the hub is not coming at a 90 degree angle (I guess going through multiple 2X4's), anyway mileage may vary...
My house is a built in the 50s california ranch home. About 2,700 square feet, single story. Hub is in the middle of the house. I have two repeaters about equidistant from each other.
All my devices in my house are rock solid, mostly zwave for switches and outlets. I use zigbee for locks and motion sensors and i have one powered zigbee outlet to help build a good mesh. very rock solid.
I have a pool house about 300 ft from my hub but on the other side of a brick wall (fireplace) from the hubs and repeaters. I get poor zwave signal there, i can pair but control is unreliable of lightswitches. The repeaters doesn't quite get it any closer. I ended up putting another hub there and its rock solid. Hub mesh makes it look like local devices and it is pretty awesome. One dashboard for the entire universe!
In my garage which is freestanding and off to the side i have a bit better zwave coverage. there are a couple of powered devices on the way there but to be honest it has more delays detecting motion on my zwave motion detector and turning on lights is sometimes a bit of an exercise. I think i'm going to put another hub there.
But the joy for me is that i can trial and error it out from the core of my home. Addind hubs as you discover issues with distance is easy and the devices work on the hub doing automation just as if they are local. With amazon prime i get two day delivery so its not like i am waiting a lot.
i got only the C7 hubs in my house.
i hope this helps.
My client's house is 3560 SqFt and I have one C-7 hub on the main floor. I have a bunch of repeaters and so far the whole house is covered even in the attic. I did add a 2nd hub (a C-5) in the garage though as it was too far from the house to be reliable - but there was an Ethernet run available fortunately.
In the future I might consider going with 2+ hubs for this size house and larger just because it seems to be the safer bet. I begin to worry about the 4 hop Z-Wave limit. Especially in older homes where signal can be easily blocked by thick walls and lath mesh..
I'm personally unconvinced that multiple hubs make sense. If you have multiple hubs, then hub-to-device transmission may occur in an overlapping pattern (that is, during "busy" times, both hubs can try to transmit at once), this can cause interference and packet loss. A single hub won't have that problem as it will ensure one-at-a-time transmission from the hub.
More technically ... I understand Z-wave is a CSMA CD network and, as is typical for CSMA CD, the controller is subject to the hidden-node problem (a general description of this topic (not-Z-wave specific) is at Hidden node problem - Wikipedia) which can be worse if there are more controllers that can end up transmitting on the Z-wave channel at the same time. Thus, it seems to me, it may be better to rely on the mesh transmission to get your data to travel throughout your home. One exception might be if you had a separate second building (e.g., a detached garage) which is out of reach from the edge of your mesh network and where you might want to put a second hub.
As a caveat, some time ago, I looked for research papers on the hidden node problem in Z-wave and haven't found anything - but its been pretty well studied in other wireless CDMA CS networks and can be a real problem at high loads. So, its possible that Z-wave does something to reduce the problem, but it doesn't seem likely.
Agree with what others have said but one additional point, larger homes typically have more devices. Early last year I had all 230+ devices, mixture of Zwave, Zigbee, and LAN in one hub but things would crawl with certain automations because say the Zwave mesh was backed up because of my goodnight routine turning everything off. I ended up purchasing multiple hubs where each is responsible for a protocol so things wouldnt impact another. This has worked out well for me but as other have said some deploy based on location. My hubs are center of my house so protocol split made sense for me.
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3500 sq/ft 1 story home fairly open layout with a lot of devices and everything is running fine.
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The most likely reason is that Z-Device traffic is in tiny packets. Tens of bytes vs 1500 for WiFi. This results in much more dead air than with Wifi. There are lots of Lab instances with many ZWave radios operating in parallel. ZWave (and Zigbee) have been around long enough that advice as to maximum number of overlapping Z-Networks would be common if it were a detectable problem, I believe.
I currently have 7 overlapping ZWave networks in this room... and of course the sphere each creates extends beyond this room. My Production set of 4 hubs (3-ZWave) are all physically at least 3 ft from one another. 3 development hubs (2-ZWave) are stacked less than a foot from my typing fingers. I have a ST hub that is only used for HubConnect questions, but it is On. And finally I have a scavenged Nortek USZB powered for use with a Home Assistant VM. I could unplug this one because the VM is shut, but I've yet to detected a problem from it.
Again, I go back to there being so much dead air as the reason for the lack of issues. I also have a Zniffer running a large portion of the time, and can see that it's not scrolling rapidly, as would be true for a 'full' airspace.
Granted, its complex to really figure out the impact of all this, but consider that a 15 byte packet at 40 Kbits / second -- i.e., Zwave, occupies the same transmit time as a 1500 byte Wifi packet at 400 kbits / second. So the hidden node problem is really one of two hubs under load - i.e., if you were turning on/off a large # of devices, causing both hubs to operate at the same time. So, the conclusion I camen to is that using multiple hubs thinking it will allow higher performance under peak loads may not be correct and you may add inter-hub coordination complexity without much benefit; but the use of multiple hubs to take care of a mesh disconnect might be worthwhile. I'd love to see an actual research paper / statistical analysis of all this, but just couldn't find one.
Me too but the only truly empirical data point I have is a visual of Zniffer. There simply is a lot of no scrolling. No scrolling = no packets (or far out of range, since weak packets will show as CRC errors.) That's on ALL 7 of my ZWave networks simultaneously. I'll usually see the Production network occupying the majority of packets, as expected. I'll usually adjust the capture to display only the Home Network# I'm interested in, thus significantly reducing the scroll. However, it is one of those things I'm curious about and will often just watch the whole spectrum (no Home Network filter.)
I have just less than 200 ZWave devices and I've often thought that the Packet per Second (pps) rate was the number I should be watching to identify another split in my collection. Right now, for those nearly 200 devices, they are split unevenly between 3 Hubs/Home Network#. For a couple of years I've had them split between just two hubs, but 6-8 weeks ago I decided I'd integrate a C-7 as a 3rd Hub and create a 'zone/area called Front' and move some devices from "upstairs" and from "downstairs" onto the C-7. It's working OK, but it's lost it's allure since there's no detectable difference. 
(In other words, I'm migrating slowly, very slowly.) All of this to validate that I do have an actual reason to watch my pps. Not as good as a research paper.. but way better than what is out there to be found 
I've stated elsewhere, a long time ago, that I think the Hubitat C-3 -- C-5 have a practical limit of 4 "Cause and Effect" events per second. (0.250 seconds per event.) My Hubs are all running in the 2 Seconds per Event range, so I have plenty of perceived headroom.
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