I have had my two Emperors for about 6 years and they have worked fine for that time. However, in the last few months I have noticed that one has slowed down a bit on it's flow and is a bit noisier. I do not see any damge to the impellor. Is it worth it to get new parts for this or should I change over to the AC? (for which I have heard nothing but good things) Thanks in advance!