intuition - Is a grayscale bar a bad way of showing temperature?

In my office there is an air conditioning unit that has a knob that adjusts the temperature with a grayscale bar with the shades getting darker from left to right above it but no other indication (such as numbers, a snowflake, etc). Sort of like this image:

This is very confusing to me. Typically I would think that temperature indicators would go from left to right (cold -> warm). But what if this isn't temperature but rather intensity where a higher intensity blast of air would result in colder temperatures? (off -> full blast)

Is white cold and black warm? Or white low intensity and black high intensity? Is it a badly designed indicator or are my intuitions off?

Bonus: What would be an idea for a better but just as minimalist design? How universal is this current design? Would snowflakes make more sense and how well understood would that be in climates with no snow? I don't think numbers would help unless they are associated with temperatures explicitly.

I took a photo of the knob. It doesn't look exactly like my illustration (in my defense it was dark inside the grid :-P )

Answer

Yes, it's bad design for its lack of signifiers (signs in the world that offer guidance).

• You can't distinguish what device it belongs to by just looking at it.


• You can't know its purpose without trying it out.


• It does't show its state clearly. Could we establish a clear relationship between one state and one temperature easily and consistently? I don't think so.

Adding one or more signifiers will help to improve it, some examples (more or less ordered from best to worst based on my preference):

• Numbers: representing temperature or "level of intensity" (the last one will also need a complementary signifier to know if the bigger number, the higher or lower temperature.)


• "Cooler" and "Warmer" labels in each corresponding extreme. Depending on the amount of states and if they really make a difference in the functionality you could add other intermediate states.


• Cooler-Warmer symbols. A sun, curvy lines (as wind), classic snow icon.


• Use of colors (warm and cold colors). Luckily for this case, blue color blindness affect less people than red and green color blindness.