Loud PSU on start up

[lwzi]

My PSU fans spins very fast and loud on start up this issue has occured 2 months ago, but it fixed it self and now it started happening again every time i boot my pc in the morning or after a few hours of not using my pc it's very loud, but if i turn off my pc and turn it on again immediatly everything is silent so like i mentioned it only happens when i haven't used my pc for few hours this makes me think maybe it's because of cold temperature in my room and since PSU is out of metal the metal absorbs the cold and the PSU temp sensors get messed up that way causing PSU fans to spin very fast once pc boots into windows sound is gone. Did anyone ever had this issue before? If it matters my PSU is "be quiet pure power 11 700w gold rated non modular" 

[--SID--]

Maybe a flipping fancontrol.

 

How is the PSU located in the case? Top or bottom, fan faced up or down?

 

What CPU and GPU?