At those distances, repeaters are absolutely going to help. The farthest I have gone was a Zigbee bulb at the end of my driveway, about 75' from my hub. To maintain communication with the bulb, I have two repeaters (SmartThings 2018 Smart Plugs) between the bulb and my hub.
The other thing you can do is get a (or a couple of) additional hub(s) and pair the contact sensors with that. Then, then link the/those hub(s) back to your "main" hub. This is something a lot of people with bigger areas do. This is the way I would actually recommend doing it unless cost is a factor.
The spec says up to 300ft open air, but that is nonsense. SmartThings lists a practical distance of 100ft open air (much more realistic).
In practice, it depends on antenna orientation and construction of walls between hub and device (concrete walls obviously impact signal more than plaster which impacts signal more than drywall).
At 45ft indoors through walls I would get a repeater(s).
I just tested a CentraLite/Iris 3320-L yesterday (and was wondering if we had a thread like this). It failed at 75 ft from the hub going through one exterior wall from the last repeater. I don't have xbee so that's an assumption as to path.
It was out on the fringe of the network, the closest wired device -which I'm assuming would be the repeater (again, no xbee)- was a Jasco/GE 45856 Wall Switch. That switch was about 1/2-way between the hub and the contact. I looked for reviews about the receiver strength of the 3320-L but didn't find anything authoritative. I'm guessing it's weak.
OTOH, the Visonic MCT-340 E had some good anecdotal reviews as to range. I haven't tried it yet.
I'm currently testing the Ikea repeaters to see how good they are compared to smart plugs. I haven't had time to run my XBee map yet though. Still letting everything I added yesterday settle in. LOL
It seems to take upwards of 36-48 hours for my mesh to fully reconfigure when I add devices. Granted, I have tons of Zigbee devices, so I'm not really all that surprised. But one thing I have learned over the years is patience.
I don't have zigbee sensors but with Zwave build for robustness, not distance. If the sensors are an important part of whatever system you are implementing, make sure you map out the sensors and what is and might be between them and the hub. Think direct line of site from the devices perspective. Something may look close but what will the radio waves need to go through to get to the hub and back. If there is machinery in between, consider the possibility of interference. Use wired in devices rather than things that can be unplugged accidentally.
It's a bit like asking how far can a car go before it runs out of gas. YMMV
With Xiaomi, I've achieved 30 feet in some locations, but only 20 feet in others without a repeater. Really depends on the building materials, other objects and how many obstructions in-between.
Add repeaters and the range issue shrinks or goes away entirely.
Hi. Appreciate your post on the additional hubs. I have a similar question. Im setting up some humidity sensors at work to monitor the humidity in electronics labs. it's a large shop and i didn't think there is any way one central hub location will cover it. For the most part, i will have network access in every lab. My initial thought was to put zwave/zigbee repeaters around the building ( loving the centralite 3210l smart plugs) but maybe the additional hubs will be a more stable option. To that point....if i did want to go say 500 feet distance would 5 repeaters be stable?
2nd question please. If i use additional hubs...do those also act as repeaters in addition to a direct link to which ever device i connect to it?
Presuming on using zigbee humidity sensors.
Thanks in advance.
Mac