Fiffaro
My understanding is that the temperature drop is the result of heat energy in the air being used to cause evaporation of water, hence the increase in humidity results in a drop in air temperature. Without windows open to allow the flow of air, to allow the water to evaporate by absorbing energy, their would be no temperature drop. Hence, water is being evaporated continuously while the unit is running. It is this continuous evaporation of water that YVW measured in a number of different units to arrive at the above usage figure. Have I missed something?
No you haven't missed anything, the evap unit is still using water. The point though is modern units use far less water than older units.