When I first got this up and running, started having the dreaded short-cycling issue. Adjusting the fan louvres seemed to solve that problem. Suspect that some of the cold air was being bounced back onto a poorly placed thermostat/temp sensor, causing a false reading. Also, the owner's manual states that in auto mode the fan will keep running when the compressor cycles off. Incorrect - the fan goes off, too. When manually going from cool to fan, the noise is barely noticeable. When it all goes off at once, it's somewhat jarring. Not to mention probably inefficient. Auto mode seems a bit erratic in general, so I don't use it. However, this unit does cool fairly well, as long as actively managed and monitored. Additionally, the vent hose is better designed than my last portable. Have had it a little over a week.