"If energy (in the world of physics) is to be compared to money, with heat the "soft currency" in the energy marketplace, then latent heat is like scrip, locally issued money, used along with regular money inside its own region (or, say, in a company store), but not outside it. Energy invested in latent heat can be used to transport heat from place to place in the atmosphere, but must be converted into regular heat before it can be radiated away at the tropopause"