I'll echo archvile here, in that I get excellent battery life running Linux. I've been getting 10-12 hours of battery life from the assortment of Asus and Thinkpad laptops I've had the past 15 years.
To give a very concrete example, I have two identical Thinkpad T14 at work, one running Linux (Debian Bookworm with KDE) and one running Windows 11. When doing normal office work, the Linux laptop easily lasts a whole workday with >20% battery left at the end. The Windows laptop runs out of battery in less than 2 hours.
To give a very concrete example, I have two identical Thinkpad T14 at work, one running Linux (Debian Bookworm with KDE) and one running Windows 11. When doing normal office work, the Linux laptop easily lasts a whole workday with >20% battery left at the end. The Windows laptop runs out of battery in less than 2 hours.