Just completed upgrading our bathroom fan to the Vortex II upgrade single speed. I found this to be a very simple yet necessary upgrade as the small fan that came with our unit just didn't move enough air. When we showered the top of the mirror got all steamed up which meant there was a lot of moisture left behind. The upgrade is just a simple drop in replacement. The most difficult part was getting the old small fan out due to the fact that it is riveted on. When testing the fan after installation I could actually feel the air move around me. Also even though this fan is larger and moves more air it seems to be less noisy than the old fan. I am also going changing out my bedroom fan to a Fantastic 4000 and my kitchen fan to a Fantastic 6600R before our next trip at the end of this month.