Air conditioning was about humidity control from the very start. Willis Carrier’s very first air conditioning system was all about controlling humidity with the side effect that it also could reduce the sensible temperature. Theaters caught on that this newfangled contraption could lead to big summer numbers when they installed it to keep patrons cool.
We often add water to the air (humidify) and remove water from the air (dehumidify) as part of our work, but let’s take a different look at what happens when we do that.