It's easy to set your sleep timer in Windows 10. Crystal Cox/Business Insider To set the sleep timer on Windows 10, you'll need to open the "Power & Sleep" menu. The sleep timer in Windows 10 controls how long your PC needs to sit idle before it'll go into its power-saving "Sleep" mode. If you're concerned with saving battery life, you should be sure to set a short sleep timer. Visit Business Insider's Tech Reference library for more stories. The sleep timer in Windows 10 controls when your PC goes into "Sleep" mode.