Ah... but there IS extra energy being used.

The water level decreases even when the top of the carafe is sealed. It would appear that the water is evaporating through the semi-porous terracotta walls of the carafe. Every gram of liquid water that evaporates absorbs 540 calories of heat energy when it turns into water vapor.

Where I am hazy is the source of the energy. One would think it would come from the air surrounding the carafe (outside) in which case the carafe should act like a miniature swamp-cooler type air conditioner and cool the room, not the contents of the carafe. Yet apparently the energy to evaporate the water from the carafe is coming from inside the carafe itself by reducing the temperature inside the carafe.

A secondary issue is how does the evaporative process manage to function through the shiny and [apparently] non-porous paint covering the outside of the carafe.

C'mon, Roger and Peter, you thermodynamicists, can you elaborate?

tanstaafl.