On our most recent IoT Podcast, Don called in to explain that the Z-Wave device furthest from his hub is occasionally dropping off his smart home network. He’s thinking of adding a Z-Wave front door lock and has added one Z-Wave repeater already. Unfortunately, the sporadic problem isn’t yet solved.
Although Z-Wave devices create their own mesh network, with each device acting like a repeater to other Z-Wave devices, the radios don’t have much range. You can expect around 30 feet of range in a best case situation. Walls and other obstacles will limit that range. Don also has the troublesome device near a metal washer and dryer, which isn’t helping either.
The other challenge is that Z-Wave uses unlicensed 900 MHz spectrum in the U.S.
A number of older devices such as cordless phones, baby monitors and some remote controls use this frequency too, which could be causing network interference. If you have any other 900 MHz devices, try to turn them off, or better yet, replace them with something that uses Wi-Fi or Bluetooth, to remove interference for the Z-Wave devices.
Our next recommendation is to remove all of the Z-Wave devices from the hub and then rebuild the Z-Wave mesh network one device at a time from the hub out. This way the furthest device will have peer devices nearby when the network is rebuilt.
If that doesn’t help, it’s probably worth spending money on another Z-Wave repeater or two. We found a two-pack for around $55 on Amazon that should resolve the issue but rebuilding the network is a free first step. Unfortunately, it’s difficult to provide a universal solution that will work since every smart home has a different configuration, various devices and other variables. But following these steps have a good chance at getting the best performance from your Z-Wave devices.
Hello,
This is all inaccurate/bad information in a big way. For one thing, older Z-Wave devices may have a range limited to 30 METERS or less because the range was not certified, but since 2014 all Z-Wave Plus devices have been range certified to 40 METERS but typically have a range of 100 METERS and the latest devices built upon the 700 series can easily go 150 METERS.
Also, battery operated devices – such as the door lock – never participate in the routing so they do not help with the mesh network.
Removing and re-adding the devices to the network is an extremely hard way to rebuild the routing – all Z-Wave gateways have a feature that will re-discover the network to avoid having to do what has been proposed. If you do want to rebuild the network manually, it is not necessary to remove the devices first – simply go through the add process again with a node that is already added, and it will update the neighbor information without changing the node ID like what happens when a node is removed and re-added, and that will save a LOT of time/effort rebuilding the system.
The 900MHz unlicensed spectrum in the U.S. was pretty much abandoned by manufacturers so interference in that range by the devices mentioned are very rare as most of those devices now operate in the crowded 2.4GHz spectrum.
The idea of using a range extender is good, but for many people a device that can be unplugged is dangerous if it is critical to maintaining the routing in the network. A better solution – if possible – is to use an installed, always powered device. So if you do not have an electrician available and are not a DIYer, use any plug-in device such as a plug-in dimmer or relay, because in the future you may want to use that device and a repeater is not usable for anything but helping the network. If you do have access to an electrician or are a DIYer, then installing another in-wall dimmer or a wall outlet that has Z-Wave will help the mesh network, cannot be easily removed, and can provide additional functionality.