Z wave and wifi don’t interfere with each other, so you don’t have to worry about that.
But WiFi can drown out nearby zigbee, particularly boosted Wi-Fi.
At my house, we have a Wi-Fi booster. If we plug it in on the north wall in one room, all the smartthings – controlled zigbee devices to the west of it drop off-line. If we just move the Wi-Fi booster to the east wall, all the zigbee devices work fine.
So the first step is to make sure that your SmartThings hub is at least 3 m away from your Wi-Fi router or any access point.
But sometimes the problem is bigger than that, and your Wi-Fi router is broadcasting on a channel which is just drowning out your zigbee devices.
You do have the option to change your Wi-Fi router, typically between channels 1, 6, and 11, so what’s the best Wi-Fi channel to use? It just depends on what your SmartThings zigbee channel is. You can see that in the IDE for your account.
WiFi Channel 11 happens to be far from zigbee channel 11, but it is sitting right on top of zigbee channel 20.
The zigbee channel is assigned randomly to your hub at the time of manufacture, so different people are using different ones.
The V1 hub couldn’t change its zigbee channel at all.
The V2 hub will randomly change its zigbee channel if you completely reset the hub (meaning you’d have to redo everything), but the reassignment is still random, you might even get the same channel the next time. So that’s usually a last resort.
As of 2021, the smartthings V3 hub and the Aeotec hub can both change the Zigbee channel through the IDE.
And, most WiFi routers will allow you to change its channel through the admin tools, so it’s usually easier to change that one.
All of which is to say that Wi-Fi channel 11 might’ve been the best one at one house, but might not be the best one for somebody else.
If you have a choice and you are running into interference from your neighbors, the following will probably be the simplest set up:
Wi-Fi router on Wi-Fi channel 11
Smartthings hub on zigbee channel 11
Phillips Hue bridge on zigbee channel 25
But if your neighbors are all using Wi-Fi channel 11 and you want to switch to Wi-Fi channel 6 or one, then you will have to start looking at your other settings individually.