Z-Wave JS slows down Home Assistant instance

Is anyone else having issues with the Z-Wave JS add-on? Every time I start it, my Home Assistant load trends up until the interface is slow beyond usable. Rebooting drops the load back down temporarily, but the only way I have been able to stop it is by stopping the Z-Wave add-on. I even disabled my 1 z-wave device and ran the add-on with no devices and it still bogged the system down.

I run hassio on a raspberry pi 3B+ with a 64 GB A2 SD card. Everything is incredibly smooth without Z-Wave running. Running on default settings with the add-on, and it used to run fine. Can’t find any errors in the Z-Wave log.

Check for a zwave device with communication issues. Look at device stats for the troubled devices.

If tx/rx dropped is high you may look at adding extenders. I would guess they have poor connection

That would make sense if the Z-Wave network was slow itself. My issue is the add-on makes the entire home Assistant instance slow. I have no z-wave devices enabled, just the add-on running bare.

It looks like you are low on RAM memory as you are trending to 95%. Add more RAM

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I probably do need to do that at some point. With Z-Wave JS off I stay at 85% it seems. May be an issue in the future. I still find it weird that the add-on uses so much ram with no devices. It must be flooding a log somewhere that I can’t find based on how it trends up RAM usage.

A year or two ago I was running HA on a Pi 3B+ (1GB RAM) and having all sorts of problems with unexplained behavior. I replaced that Pi with a Pi4 with 8GB RAM and the problems went away. Watching the memory on the Pi4, I noted that the memory usage now hovered around 1.2GB - i.e., more RAM than the Pi3B+ had. My suspicion is that as I installed more integrations the RAM usage on the Pi3B+ had increased, and finally the Pi was spending a lot of its time swapping data between the internal RAM and the external SSD. My conclusion was that RAM usage above 60-70% was to be avoided. For the last year or more, no problems on the Pi4 with memory usage below 25%.

My suggestion would be to try a Pi with more RAM (SSD or SD card size isn’t the issue). You could also try disabling or temporarily de-installing some less important integrations to get memory utilization down below 50% and see what happens with ZWave.


Pulled the trigger on an 8GB raspberry pi 4 and simultaneously swapped from SD to SSD. All add-ons are running and everything is smooth as predicted thanks to the rpi4 increased RAM. Must have been on the bleeding edge with the pi 3B+ as you suspected, thanks!

You’re welcome! Glad I could help after all the help I’ve gotten from the HA community.

One other suggestion… I noticed that memory usage would creep up over several days of HA operation even after I switched to more RAM. That might indicate a “memory leak” somewhere in some code.

Rather than trying to track it down, I just set up a simple automation, which just restarts HA every day at 3AM. I’m not sure it’s necessary, but it doesn’t hurt as far as I can tell.

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