I must say, I've tried other air purifiers but this unit is the pinnacle of them all.  It is a beast of a machine.  It features multiple fan modes as well as other features that will easily purify the air of a large space.  I can't get over the size of it.  It is built really well and of quality materials.  The filters are easy to clean and manage and the unit isn't loud at all.  I suggest everyone get this product ASAP.