Fan noise MacBook pro retina 13 "

Hello everyone,

am new to the forum and I'm not sure to write in the right place, so if I'm wrong let me know, thank you ... and sorry for my Inglese.

Aside from that, I wanted to share with you if you can call it my "problem" or not.

I have a macbook pro retina 13 '' (Yosemite - acquired in December 2014) and every time I turn it on I always hear the hum of the fans despite no applicazioneicon1.png is open.

This "buzz" you hear it only in areas where there is absolute silence.

For example, when they are in ufficioicon1.png, that I have no sound / noise in the room, from my Mac comes this annoying noise.

I have read of cases that the fans were leaving at most for no reason, but this is not my case ... the "buzz" is heard in circumstances of absolute silence and is constant and feel good just bring your ear next to the button ignition.

I tried to see if I have some process that takes too much CPU, I did reset without reintroducing the backup, the fans are clean and free of dust.

I wanted to ask: is a normal thing or do I bring it in for service ???

Thanks a lot in advance.