My husband refused to go anywhere requiring AC because of the noise. Since we live in the Rocky Mountains, it is usually not a problem. However, since we plan on attended the Phoenix reunion in Charleston, I needed to com up with a plan. We just installed, at great expense, the Houghtn AC unit. It was developed in Australia and is sold in the US exclusively by Advanced RV in Ohio. There are a couple YouTube videos about the sound...9 decibels quieter than the next best (which I think was the Coleman). Was $2,100 plus $250 shipping to Denver. Cost about $500 to have my excellent small RV shop in Denver install. If you got to Advanced RV in Ohio, costs about $2,700 installed--so more or less a wash. Required getting a separate thermostat for the furnace. When the owner of the RV shop (who originally thought I was nuts to replace a perfectly good AC at such great cost) called to say it was installed and working, he said, "My tech is standing here with icicles hanging off his beard and was able to listen to his iPod while int he RV." Owner was so impressed, he was going to look into becoming a US distributor. Have not been anywhere really hot overnight to test the true efficiency, but what we have experienced so far in testing and just cooling down for a lunch stop or when arriving at a campground, has us so glad we spent the money.