Hi,

my environment is running since openhab2. For openhab4 I decided to transfer my rules to UoM and encountered a problem, when using items (with default unit kWh) and multiplying with a dimensionless number. The result is weird and I do not know why openhab is calculating in Joule (instead of kWh).

I defined the following items:

```
// Test Switch
Switch TestingActive "Testschalter"
Number:Energy SomeValueInkWh "Number in kWh [%.3f %unit%]"
Number:Energy SomeValueInJ "Number in J [%.3f %unit%]"
Number:Dimensionless weatherActClouds "Bewölkung: [%.0f %%]" {channel="openweathermap:weather-and-forecast:api:local:current#cloudiness"}
```

In my rule I do the following calculation:

```
rule "ShowCase"
when
Item TestingActive changed to ON
then
SomeValueInJ.sendCommand(5)
SomeValueInkWh.sendCommand(5)
logInfo("Show case", "Wrong UoM J vs kWh :{}", SomeValueInJ.state)
logInfo("Show case", "Part 1.1 of multiplication :{}", SomeValueInkWh.state)
logInfo("Show case", "Part 1.2 as Number of multiplication :{}", SomeValueInkWh.state as Number)
logInfo("Show case", "Part 1.3 as Number with 'J-recalc' of multiplication :{}", SomeValueInkWh.state as Number/3600000) // 3.600J * 1000
logInfo("Show case", "Part 2.1 of multiplication :{}", weatherActClouds.state)
logInfo("Show case", "Part 2.2 as Number of multiplication :{}", weatherActClouds.state as Number)
val Number result1 = (SomeValueInkWh.state as Number) * (weatherActClouds.state as Number)
val Number result2 = (SomeValueInkWh.state as Number/3600000) * (weatherActClouds.state as Number)
logInfo("Show case", "Result 1 (Part 1.2 * Part 2.2) :{}", result1)
logInfo("Show case", "Result 2 (Part 1.3 * Part 2.2) :{}", result2)
end
```

The result in the log is as follows:

```
2024-01-28 20:51:13.426 [INFO ] [.openhab.core.model.script.Show case] - Wrong UoM J vs kWh :5 kWh
2024-01-28 20:51:13.430 [INFO ] [.openhab.core.model.script.Show case] - Part 1.1 of multiplication :5 kWh
2024-01-28 20:51:13.433 [INFO ] [.openhab.core.model.script.Show case] - Part 1.2 as Number of multiplication :5 kWh
2024-01-28 20:51:13.439 [INFO ] [.openhab.core.model.script.Show case] - Part 1.3 as Number with 'J-recalc' of multiplication :5.00000000
2024-01-28 20:51:13.442 [INFO ] [.openhab.core.model.script.Show case] - Part 2.1 of multiplication :0.05
2024-01-28 20:51:13.445 [INFO ] [.openhab.core.model.script.Show case] - Part 2.2 as Number of multiplication :0.05
2024-01-28 20:51:13.457 [INFO ] [.openhab.core.model.script.Show case] - Result 1 (Part 1.2 * Part 2.2) :900000.00
2024-01-28 20:51:13.459 [INFO ] [.openhab.core.model.script.Show case] - Result 2 (Part 1.3 * Part 2.2) :0.2500000000
```

As one can see the passed “5” leads in any case to 5 kWh (even if I give as name Joule; expected).

But when I multiply this number with any dimensionless number openhab is transfering the kWh to Joule.

Where is my mistake? Which other UoMs are transfered to the “non-default unit”?

All manuals and discussions tell, I can put whatever I put, but calculation is done in “default unit”.