List of valid "unit_of_measurement" options?

Configuration
1

I’m trying to find a list of the valid units of measurement? In setting up a battery meter would it be “volt”, “volts” or “v”?

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It’s ‘V’

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3

To be clear, unit_of_measurement is just a string and can be anything you want. There are only a few “special” uom values, such as “°C” and “°F”, where HA actually converts values to your locale settings when it sees them. Otherwise, “Pigs Flying” is a perfectly acceptable unit_of_measurement as far as HA is concerned.

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4

Thanks Rob… That makes sense… What then controls HA treating it as a number and making this show as a line chart?
image

I can see that in the History area HA is treating it as a number…
image

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5

Okay, apologies… It looks like the sensor had not yet received an update… Now that it has received an update it is showing as a line chart… Nice!
image

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Right, it just needs to have some unit_of_measurement, doesn’t matter what it is. Sometimes previous values without a uom can delay the graph displaying until they’re flushed out with new data.

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7

Thank you for explaining. Is there a list of the “special” uom values which get converted?

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I suspect that it’s these: core/unit_system.py at 0b4b071c0238999f5af5c4d391478ec87e545d21 · home-assistant/core · GitHub

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Only c and f get converted. Everything else remains untouched

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That’s what I thought, and then I saw the conversion functions for other things. I guess those are just helpers for integrations to use when they want. Incidentally, the frontend changes the icon when it sees a temperature unit: frontend/sensor_icon.ts at dc79fc2919d836ae28ce0c065aacd6ef52f47dc7 · home-assistant/frontend · GitHub

  const unit = stateObj?.attributes.unit_of_measurement;
  if (unit === UNIT_C || unit === UNIT_F) {
    return "hass:thermometer";
  }
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This does not seem to be true for long term statistic see problem reported here

12

To historize the states of my Venstar thermostat attribute: hvac_action
what unit_of_measurement should be used for different text strings like idle, cooling, etc.?

So far, with this configuration:
HVAction

when I pull it up in history it’s trying to trend a numerical value.

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To clarify, the variable is acquiring the data:

HVACTION1

But the history is either not being stored or retrieved properly:

HVACTION2

Is unit of measure the problem, or something else?
Ideally, the trend would show up like the weather forecast:

HAWF

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if you add a unit of measurement, it attempts to graph it. So don’t add a unit of measurement.

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15

That’s it, THANK YOU!!!

HVACTION3

16

i have a similar issue. i have no uom but i still see a line graph. any thoughts?

17

that’s the only thing that causes it unless something changed recently.

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18

Would state_class: being present perhaps cause this behaviour too?

19

It could. To be honest, I haven’t been paying attention to those details lately.

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20

This doesn’t make sense. Does it mean that Home Assistant only supports dollars, euros and cents as currency unit of measurements? What about the rest of the world?

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