It is my impression that the aforementioned terms are primarily used to describe styles of speech or writing. A more technical style which focuses exclusively on conveying the idea as precisely as possible, and which perhaps adheres to some particular well-defined style guidelines (as, for example, this sentence and the preceding one), is considered cold.

On the flip side, when you're more conversational, try to get across some sort of emotion, or just generally appeal to the person you're addressing (in a friendly way!), that's more warm.