Question about portable AC units

Hi all, I'm currently working on laying out plans for a grow room. I'll probably end up using either a 400w or 600w HPS so it may get a little hot. The room will be the size of a normal bedroom and have a portable ac (the kind that have the hose that goes into the window, not the ones that the whole unit sits in the window) in the room to help keep overall ambient temperatures down. I have a question though, does anyone know of a portable ac that actually allows you to have cold air output through a duct instead of the vents built into the AC unit itself? I have looked around forever for something like this so that I could force-air cool the HPS but only the HUGE thousand $ and up coolers made for commercial use have the tubes. I was looking for something in the more like $200 - $400 range.

Oh, and another question:

Lets say I have a 3' x 3' space in which I use to grow inside of a larger room. At some point this space may be expanded to 5' x 5'....I don't know yet. I can't realistically right now buy a grow tent, and I'd rather not build one. I have been under the impression that if I grow in a larger room, the lumens from my lighting setup will become "lost" in this extra space....is that correct? Well, I was thinking of going to home depot and buying some particle board or white-painted metal siding and just enclosing the grow area. The "walls" wouldn't reach the ceiling, but they would be taller than the where the grow light would hang from. Would this be adequate?

I would try and keep it simple and get complicated only as needed. Get your room up and running and see what the temps are like before you worry about AC.

I think your idea for enclosing the grow is very good and would work. How much it will increase the amount of actual lumens getting to the plant I know not though.

Good luck.

Have you seen these youtubes on growing rooms?

YouTube - how to grow marijuana at home-part 1
YouTube - How to Grow Green

here is a thought-check out watercooling kits for PCs. you can buy setups that come with a radiator that you attach to a hot PC part and water rushes over the back of it to take away the heat and dissipate it through the radiator. I would imagine you could attach one to the hot parts of the ballast, no water actually comes out just make sure its tight and not leaking before you turn on the lights naturally. these kits are designed for computers so leakage is usually not an issue or they wouldn't be in business. you could get a nice kit in your price range.