Silent laptops which stay silent under linux

[chooback]

Hi,
I'm planning on buying a new laptop. The key feature is that it should be silent. I spend a lot of time writing latex documents in an otherwise empty room, so the fan should really not kick in too often. On top of that I use linux.

I thought about three choices which are in my budget:
Asus UL50
Acer Aspire Timeline (I know there are many models - maybe some are more suitable than other?)
Lenovo U550

All of them are CULV laptops.

I would much appreciate any comments from users of those laptops, preferably those which have linux running.