Hello,
First, happy new year 2016 to everybody !
Globally, the desktop computers with Linux don't save the battery so long than those with Windows, (and maybe than those with Mac Apple) : about 3 hours with Linux and more than 6 hours on Windows. (no test with Apple).
This is a (rare) serious inconvenience for Linux.
The kernel doesn't manage correctly the energy usage of the battery, compared to Windows.
Hope it will better in a few months, this is important for the travellers.
André