I received the 630 model as a gift for my living room. I have a 550 in my bedroom. While the model does circulate the air, in order to remove the grill to CLEAN it, you have to remove 3 screws. The screws are at the end of an extremely NARROW, LONG hole that requires a special not your run of the mill screwdriver. After I purchased that I spent the better part of a HALF HOUR trying to get the screws out. I got 1 out of 3 and lost 45 minutes of my life I'll never get back AND I still have a filthy fan. Not happy. Won't be buying another fan that makes it so difficult to keep clean.