If you want your fans to spin often it requires changes in the BIOS (or whatever its called)... If you know how to change your laptop settings then you can change the temperature at which the fans start spinning..
But I think that is a good sign. If your fans are spinning less then it means that your PC is getting less hot.. This means your laptop does the same work with less power..
If you want it to spin before it gets hot just reduce the temperature at which it starts spinning (requires changing settings in BIOS which is not recommended by me)
But I think you should rather let it be the way it is