What's the deal with preferred sensors scales in zwavejs2mqtt

Configuration Z-Wave
1

Select preferred sensors scales. You can select a scale For more info check https://github.com/zwave-js/node-zwave-js/blob/2e73eccea3b50ec8e112130e6ed83ac8919ec7c8/packages/config/config/sensorTypes.json

I can set all units to preferred units, like °F or °C or more exotic ones that I don’t even have sensors for.

Should I set this? I guess HA decides whether it shows °C or °F, but of course if it only sends °C it would be less traffic…

2

It affects how Z-Wave JS queries for sensor values (or anything else that takes scales). If you set F as a preferred scale, it will attempt to always query temperature values using the F scale (if the device supports it). If a preferred scale is not set, it will just choose which ever is the first supported scale, e.g. a device might say it supports with C and F, and C is the first.

It doesn’t have any impact on network traffic.

3

This setting is essential for some devices,

For example, what I saw is initial values for thermostats coming through in C even though HA was in F. 65 F ~= 18 C. So HA was showing 18 F, then on next update it would show 65 F.

Ran into the same problem with Lux vs % for light sensors.

For me if effected initial values after a network restart and then self corrected, but once I set the preferred units it was always correct.

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