This air conditioning unit is cooling an area bigger than it is rated for.  It is working perfectly.  It is a bit louder than I expected, but that is not noticeable unless I am sitting close to it.  Even then, the noise level is satisfactory.  My only problem was that the width of the unit was 1/8 of an inch more than the specification and the advertising stated.  As a result, I had to modify the installation site. That was the reason I subtracted one star.