There are several things you can do to make it a better environment for your plants.
For one, enclose it in clear plastic. It will still allow light in from the window, but will be good containment for heat and humidity. On the back and sides, you can use the "interior storm window kits" from 3M - you put double stick tape on the outside framework and stick the film to it, then shrink it with a hair blow-drier, and you can hardly tell it's there. I just drape a piece of plastic for the front, but I have also seen folks make a lightweight, removable frame and use the same film.
Humidity does not really rise or sink, it fills the volume it's in uniformly (another reason to enclose the rack, so that's what you're humidifying, not the whole room).
Both the warm- and cool mist humidifiers have advantages and disadvantages.
The "warm mist" types insert a hearing element into the water and the vapor is usually blown gently out. It can add slightly to the temperature in the environment. Minerals in the water will deposit over time onto the heating element, reducing its efficiency.
"Cool mist" varieties come in many flavors: those with wet wicks through which the air is blown to evaporate the water (that's where the minerals will deposit, so you have to replace the wick periodically), simple mechanical atomizers (usually spinning disks), and ultrasonic atomizers. Any device that atomizes the liquid will send the dissolved minerals out in the mist, so it will show up as a white dust film on everything in the environment. The use of pure water eliminates that, but I have heard reports that some ultrasonic types won't work with pure water.
My advice is to find one that you're comfortable with from safety, appearance, size and sound level perspectives, and don't worry about it. The negatives are small and easy to deal with.
|