It gets to 90-120f outside. Inside my place it is 80f. And humidity is only 30% inside my home. So there should be little if any condensation dripping from unit. But just to be on the safe side, I have it over a metal pan.
I ran it for 4 hours last night, and not one drip of water. And yes cool air is heavier so it is down low, but having the unit down low will make it cool my room better. Cool air in, Cold air out..... Hot air in, cool air out. AC units do not work very well when they have 120 degree air entering them. In that 4 hours of running it, I was able to get the room down to about 66f. So once I start my HPS light up, I am hoping I can keep the room to 75-80f. My last grow I saw temps in my room all the way to 94f. And this was not even during the hot part of the year.

If humidity raises above 40% I will buy a dehumidifier. But I really doubt this will happen, because A/C units dry out the air, they do not put humidity in the air like a swamp cooler does.

I am thinking about moving my plants in there sooner then flowering stage now. Maybe next weekend when I have to do another Res. Change out.

Crazy, I am thinking where you live is a lot more humid there here. Like right now outside humidity is only 3%. (Yes, 3%). I live in the Desert.

Oh, another thing to remember, the rest of my home is also Air Conditioned, which means that larger unit will be removing moisture also. But I will deal with what happens when it happens. The unit can not be routed outside. It is what it is.