I'm getting really low battery life under ubuntu, not even close to windows. I tried powertop, and I saw that my laptop is consuming in idle nearly 20 watts (a bit more).

I tried to install laptop-mode-tools, change "good" into "bad" in powertop, but nothing changes. I see that I have the the HD audio output device which is running at 100% every time. Could this be the problem?

This is a report from powertop.

The battery reports a discharge rate of 22.8 W
The estimated remaining time is 33 minutes

Summary: 381.8 wakeups/second,  0.0 GPU ops/second and 0.0 VFS ops/sec

            Usage       Events/s    Category       Description
          3.2 ms/s     182.7        Timer          tick_sched_timer
        100.0%                      Device         Audio codec hwC0D3: Intel
          7.9 ms/s      25.1        Process        /usr/bin/X :0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch -background no
          1.9 ms/s      24.2        Interrupt      [6] tasklet(softirq)
          2.9 ms/s      23.2        Process        /usr/lib/chromium-browser/chromium-browser --type=zygote
          8.1 ms/s      20.3        Process        /usr/lib/unity/unity-panel-service
          0.7 ms/s      17.4        Timer          hrtimer_wakeup
          4.2 ms/s      12.6        Process        unity-2d-panel
        604.4 µs/s       9.7        Process        syndaemon -i 2.0 -K -R -t
        149.7 µs/s       9.7        kWork          ieee80211_iface_work
          0.8 ms/s       8.7        Process        metacity
         19.5 ms/s       1.0        Process        powertop
          3.0 ms/s       6.8        Process        //bin/dbus-daemon --fork --print-pid 5 --print-address 7 --session
        699.0 µs/s       6.8        Process        /usr/lib/thunderbird/thunderbird
          4.3 ms/s       4.8        Process        gnome-terminal
        658.9 µs/s       2.9        Interrupt      [1] timer(softirq)
         75.1 µs/s       2.9        kWork          iwl_bg_run_time_calib_work
        163.8 µs/s       1.9        Process        /usr/lib/accountsservice/accounts-daemon
         70.6 µs/s       1.9        Process        [ksoftirqd/2]
         25.8 µs/s       1.9        Process        [ksoftirqd/0]
          1.0 ms/s       1.0        Process        /usr/bin/python /usr/sbin/powernapd
        408.2 µs/s       1.0        Process        unity-2d-shell
        189.8 µs/s       1.0        Process        /usr/lib/chromium-browser/chromium-browser
        124.4 µs/s       1.0        Process        /usr/lib/unity-lens-applications/unity-applications-daemon
        113.3 µs/s       1.0        Process        /usr/lib/gnome-settings-daemon/gnome-settings-daemon
        112.0 µs/s       1.0        Process        nautilus -n
        104.9 µs/s       1.0        Process        /usr/lib/gvfs/gvfsd-trash --spawner :1.2 /org/gtk/gvfs/exec_spaw/0
         77.5 µs/s       1.0        Process        /usr/lib/x86_64-linux-gnu/colord/colord
         75.6 µs/s       1.0        Process        /usr/lib/gvfs/gvfs-gdu-volume-monitor
         75.0 µs/s       1.0        Interrupt      [53] i915
         74.9 µs/s       1.0        Process        /usr/lib/gvfs/gvfs-afc-volume-monitor

What should I do to make the battery consumption lower?