I have something similar to this.
http://www.costco.ca/Browse/Product....=1&topnav=&s=1
Only with one hose.
Here are my observations.
If you put it in a bedroom it cools it after about 2 hours if it is 30C outside.
I put it against my screen door, if I set the timer to start at 4pm then its comfortably cool in my place if I keep the 2 bedroom doors closed when I get home at 7pm.
I like the portability and the fact that I can move it without hassle of unscrewing anything. Also the timer is bloody easy to use and very useful.
I purchased it last summer as it was unbearable in my condo, I would sit and watch movies on the weekend and lose half my bodyweight to sweat on my leathe couches.
Michael.