FAQ: How to improve the performance (responsiveness, speed) and reliability of a Z-Wave mesh

This is a very common issue that folks will face when using Z-Wave devices. Over time you’ll see that your device connectivity gets slower, commands take longer to execute (higher latency), sometimes they don’t execute (loss of packets).

This happens due to a variety of reasons and this Wiki will provide you with some tools to fix these issues. While this isn’t a magic bullet to fix all Z-Wave problems, it should resolve the majority of common issues with a Z-Wave Mesh.

I’m not going to get into how a Z-Wave Mesh operates or Z-Wave vs ZigBee, but I will focus on 3 key issues that can severely impair the performance and reliability a Z-Wave mesh.

  1. Ghost devices: Ghost devices are devices that are no longer connected to the mesh but they still show up in the routing tables of the hub (controller). These can cause significant havoc in the mesh including slowdowns, high latency, random unresponsiveness and even loss of packets in the worst case scenario. This article talks about how to identify and get rid of ghost devices: FAQ: How to remove ghost devices from your z-wave and zigbee networks

  2. Buffering devices and repeaters: Lack of buffering devices causes loss of packets in the mesh. This is one of the most common issues especially when using battery powered Beaming devices like Smart Locks, Battery Thermostats, Battery Sirens etc. Typical symptoms include random loss of connectivity, inconsistent operation etc. TLDR; make sure you have atleast a few mains powered Z-Wave Plus devices (like outlets, plugs, thermostats etc) which can act as beaming repeaters to keep the mesh strong and avoid issues related to a weak mesh/signals. This post explains it great length and also provides recommendations on how to fix these issues and which devices act like beaming repeaters: FAQ: why would I need another beaming repeater if my zwave lock is already close to my hub?

  3. Mesh repairs: Over time when you add/delete and move devices around the house, the mesh routing information isn’t always up to date. This can cause a general slow down in the mesh due to in efficient routing. You can a Z-Wave repair using the SmartThings app. Keep in mind this process generates a LOT of traffic between all the devices while they discover and update the routing tables and can often make the mesh very slow/unresponsive while the repair in process. This process can take from 10 minutes to an hour depending on the number of device in the mesh so keep this in mind when timing when to run a repair. Also it’s not recommended to run a repair very often, typically only when there are changes to the mesh (add/deleting devices or moving device locations) should this process be run. Click here to read how to do a Z-Wave repair using the SmartThings mobile app.

  4. Offline repeater devices: If you have a mains powered repeater device which is permanently offline (e.g. no longer used), it can help to remove those devices from your SmartThings setup. While technically after doing a Z-Wave repair it should compensate for devices which are offline and avoid routing through them it can improve the overall mesh quality to delete these devices from your controller/hub using the SmartThings mobile app. It’s best to always exclude devices if possible but as a last resort you can delete them from the SmartThings mobile app (preferred over deleting them from the IDE).

Feel free to share your feedback and I will keep this Wiki updated.

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Very nice!

One small point:

That is a recommendation from smartthings support. It’s not a common Z wave recommendation, and in fact most of the competing hubs recommend that you do run a z-wave repair at least once a week just as part of regular maintenance. Some platforms even do it every night.

I don’t know why things seem to be so different on the smartthings platform, but it is true that smartthings support has from time to time said that running a repair can make something worse rather than better. I don’t know why that would be, but I have come to accept it as a platform idiosyncrasy. I just didn’t want people to think it’s a normal part of the protocol. :wink:

Great post. Thanks.

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From our testing here the newer firmwares seem to do a much better job of handling Z-Wave repairs. Some folks tend to do back to back repairs which can really overload the mesh due to the heavy traffic that’s generated during a z-wave repair which can leave the mesh unresponsive. The same reason it’s also not recommended to operate devices during a Z-Wave repair as it may also interfere with the repair operation.
A simple example, on one of our test hubs which had about 40 odd z-wave devices spread across about 5000 sqft through rooms/walls, I noticed that response time for some switches was about 3-4 seconds. While running a Z-Wave repair which lasted about 30 minutes I noticed the response time increased to over 30 seconds for some beaming devices. After cleaning the mesh up (also found a few ghost devices) and once the traffic had settled down post the z-wave repair, the response time for the same switches was now under a second.

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Right, my point was just that on most platforms, running a zwave repair/heal is considered a normal part of regular maintenance, not just confined to when you add or remove devices. Vera, for example, is set up to run a repair every night. Homeseer has long recommended running one once a week. I never heard of a support operation telling someone to not run a zwave repair until smartthings, so I’m assuming that has something to do with the cloud structure. When I was a field tech, that was the first thing you did, just to clean up any potential issues. You ran a zwave repair the night before and then started doing individual diagnostics the second day. But that wasn’t a smartthings environment.

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I’m suggesting to use Zwave Analyzer together with Zware Repair. You will be able to see your Zwave Mesh tables before the repair and after the repair. This will give you confident that something had changed. Look also here:
FAQ: Is there a way to see the Zwave mesh network map?

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