With high confidence I can say the bearing temperature on AC fan doesn't impact temperatures. Bearings are size of finger tip and the only heat source. The fan casing temperatures actually dropped when I tested yesterday with thermal gun and with everything exhausting out the top I don't see any increase at sensor.
Today cloud cover so no solar advantage with higher speed AC fan with the warmer bearings 96° #1 AC fan and #4 Davis solar are side by side while #5 is my Rainwise backup unit located about 20' away.
All have SHT31's and temperatures within .1 all day. Biggest difference is humidity with #4 sensor reading 2-3% lower but it always reads lower humidity in mid ranges but catches up as humidity rises into 90's.
Didn't realize they were making 100% efficient AC motors these days.
Seriously? If a motor was SO inefficient as to cause heat to be transferred to the sensor, you'd eventually be replacing a burned up motor. These are case fans, not 100 HP building ventilation fans.
Seriously. They draw a certain amount of power. A fair portion of his is turning to pure heat.
No joke. The part you don't want to understand is that it's negligible, if not non-existent at the sensor location. I've used my 67CFM fan for over two years and my obs sure as hell compares very favorably to the ASOS's in my area. I guess their a/c fans must be effecting their obs as well. 
It might only be a few tenths. Which wouldn't register at ASOS. If it's registering as a 20-40 degree rise over ambient it certainly isn't negligible. It's your accuracy that suffers anyway. Oh well.
Oh? Why would an ASOS not register a few tenths?? Considering I've dealt with ASOS's professionally since their inception, that's surely news to me.
20-40 degree rise? Where's that coming from
My accuracy suffers? You have no idea what you're talking about and are merely arguing for the sake of trying to save face.
Quit while you're behind, unless you want to continue your uneducated points.
