What is CalNCService and why does it run hot in macOS Sierra?
I had same problem (fans at full throttle, CalNCService at 122% of CPU) and have made 2 visits to Apple store and 3rd visit I checked in the Mac for a warranty repair (replaced both fans)...  Yet the problem continues.

I went into notifications > edit and disabled all notifications, badges, sounds, etc, except for iMessage, Slack and Outlook.  

About 3 minutes later, I noticed.... silence.  Fans are normal.  I'll watch it for a while, but it seems this issue is definitely related to something in notifications.  I won't miss being pinged all day long.