Hardware gets more efficient every year, but the settings on today’s devices decide most of the electricity they actually use. Each of the five changes below takes a few minutes, costs nothing, and shows up on the meter within a month.
Sleep timers and display timeouts
The single highest-yield setting on any computer. A 27-inch monitor and a desktop idling overnight draw 60 to 90 watts doing nothing: 500 kilowatt-hours a year in an office that leaves ten machines on. Set laptops to sleep after 10 minutes of inactivity and displays to switch off after 5. On Windows this lives in the power plan settings. On a Mac it is in Lock Screen. On a phone, drop the auto-lock to 30 seconds. Daily use feels the same, because the machine wakes in two seconds.
Brightness, and the automatic setting underneath it
Displays are the largest single load in a laptop and often in a room. A 15-inch laptop screen at full brightness draws 8 to 10 watts; at 40 percent it draws 3 to 4. A 27-inch external monitor runs 25 to 40 watts depending on brightness and panel type. Turn brightness down to the lowest comfortable level and enable the ambient light sensor if the device has one. While in the same menu, dropping a high-refresh-rate screen from 120 hertz to 60 hertz saves another 10 to 15 percent of display power on phones and laptops that support the option.
Efficiency mode on laptops
Every major operating system now ships a power mode slider, and the default is rarely the most efficient one. Windows calls it Power Mode and offers Best Power Efficiency. macOS has Low Power Mode in the battery settings. ChromeOS has a similar switch. Efficiency mode trims processor frequency and background activity, typically cutting full-load power by 20 to 30 percent. For office work and video the difference in responsiveness is small. While there, set any laptop that lives on a desk to stop charging at 80 percent, which reduces battery heat and slows the aging that eventually forces a replacement.
Kill switches for standby loads
Chargers, speakers, printers, and set-top boxes draw power every hour whether or not they are in use. The cluster under a typical television adds up to 8 to 15 watts, which is $30 to $60 a year at European prices. A switched power strip costs $15 and turns the cluster off with one click at night. A smart plug with a schedule costs $25 and does it automatically. Neither requires any change in habit beyond choosing which devices must stay on. The router and anything security-related should stay powered; almost everything else can wait until morning.
Router and Wi-Fi scheduling
Networking gear runs around the clock by default, and most routers now ship with power settings that almost no one opens. Look for an Eco mode or a Wi-Fi schedule in the administration panel. Scheduling Wi-Fi to switch off from midnight to 6am on a home connection saves 25 to 40 kilowatt-hours a year on a router drawing 10 watts, and the household notices nothing except that phones reconnect when the kettle goes on. Some routers offer per-radio control, where the older 2.4-gigahertz band can be switched off entirely if nothing in the house still needs it.
Taken together, these five settings typically cut a home office’s electricity use by 150 to 300 kilowatt-hours a year, and an office with ten desks by ten times that. The devices themselves change rarely. The settings change whenever someone decides to look.