It can certainly be tricky to get a zigbee home automation network deployed properly due to possible Wi-Fi interference. Control four is professionally installed by technicians who have network mapping tools and devices are limited to those with official device handlers. The same is true for the mid tier offerings from Xfinity, Time Warner, etc.
Typically if you’re going to have Wi-Fi interference, you would notice it with an individual new device at the time that it was added to the network. Or, if you added new Wi-Fi equipment in the home.
It’s just really rare That an individual motion sensor, for example, would work great for several months and then suddenly fail because of interference if no new devices have been added in the home. It’s much more likely to be one of the problems mentioned in the sensor FAQ:
That said, you may have noticed that I haven’t been recommending this FAQ to most of the people reporting zigbee sensor failures over the last month or two.
That’s because those people are reporting that multiple devices are all failing at once and that this failure often follows a hub update or outage.
That’s not common for zigbee unless someone has added new Wi-Fi equipment. ( in which case you may just have to treat it like a brand-new network installation and you may end up having to move a few devices or add some more repeaters.)
But the mysterious “I haven’t changed anything and now the motion sensor is always reporting active” is something else. And most likely platform related, not protocol related.
But obviously I can’t know for sure. And different people may have problems caused by different issues.
A note about why the zigbee alliance says wifi shouldn’t be a problem
I also wanted to comment on the passage you quoted from the zigbee alliance about zigbee as a robust protocol.
As far as Zigbee and Wi-Fi interference, the zigbee standard offers methods to help reduce the impact of interference, but it’s up to each manufacturer which of those they want to implement. Smartthings, for example, does not utilize dynamic channel assignment.
http://research.microsoft.com/pubs/138258/sensys10-final172.pdf
In addition, as you’ve probably seen me recommend before, optimal zigbee deployment would include at least two repeaters per zone, and most control four installations will have at least that many.
SmartThings is sold to many people who want to spend as little money as possible. The kind of people who take apart a $15 lightbulb so they don’t have to buy a $40 sensor. Given that market niche, it’s probably not surprising nothing in the SmartThings materials recommends multiple repeaters per zone.
So I do think it’s fair for the zigbee alliance to say that Wi-Fi interference shouldn’t be a big deal. But that’s in a network that is designed to address that issue. Not just a few random zigbee devices attached to a single channel Coordinator.
All of that said, however, I’m not convinced any of that would help with the problems that people have been reporting recently where multiple devices that used to work suddenly stopped working. To me that looks like a cloud issue, not a zigbee issue.