The TV PLUS box is fully compliant with the current CH and EU energy efficiency norms. It uses about 4W in full operation and around 0.5W in standby mode.
If you are not using the box for about 3h it will automatically go to standby to conserve energy and your Internet bandwidth. To wake up from standby, the box typically needs about 4 seconds after you press the power button.
Incidentally, the cold boot (when you connect the power cable) takes 30-40 seconds, so that's fast too.