The biggest power drains on a desktop or laptop are the processor, graphics card, and display
A typical desktop computer uses between 100 and 800 watts depending on its components, while a laptop uses 20 to 100 watts. The actual cost depends on your local electricity rate — check your power bill for the per-kilowatt-hour price — but reducing power draw cuts that bill directly. The most effective changes target the parts that run constantly: your CPU, GPU, and screen brightness.
You do not need new hardware to see results. Most savings come from changing settings in Windows or macOS, adjusting how your computer sleeps, and closing programs that run in the background. A few changes can reduce power draw by 20 to 40 percent without affecting everyday performance.
Key Takeaways
- Lowering screen brightness and enabling sleep mode when the computer is idle saves the most power with no effort after setup.
- Closing background programs and disabling unused features like Bluetooth and Wi-Fi when not needed reduces constant power draw.
- Switching to a power plan designed for efficiency rather than performance cuts CPU power use without slowing typical work.
- Older monitors and power supplies waste more electricity than modern ones, so upgrading these components pays back over time if your PC is more than five years old.
Adjust your display brightness and sleep settings first
The display is often the single largest power consumer on a laptop and a significant one on a desktop. Reducing brightness to a comfortable level — not maximum — cuts display power by 30 to 50 percent. On Windows, open Settings, go to System > Display, and drag the brightness slider down. On macOS, use System Settings > Displays. Most people find 40 to 60 percent brightness adequate for indoor work.
Sleep mode is equally important. When your computer sleeps, the CPU and GPU use minimal power while the display turns off. Set your computer to sleep after 5 to 15 minutes of inactivity rather than running all day. On Windows, go to Settings > System > Power & battery > Screen and sleep, then set "When plugged in, turn off after" to your preferred time. On macOS, use System Settings > General > Sleep. A computer that sleeps 16 hours a day instead of running continuously can cut power use by half.
Switch to a power-saving plan and disable background programs
Windows and macOS both include power plans that reduce CPU speed and voltage when full performance is not needed. On Windows, right-click the battery icon in the system tray, select "Power settings," and choose "Power saver" or "Best battery life" instead of "Balanced" or "Best performance." On macOS, go to System Settings > General > Energy Saver and enable "Reduce motion" and lower the "Turn display off after" time.
Background programs drain power constantly. Open Task Manager on Windows (Ctrl+Shift+Esc) and look at the CPU and disk columns — anything using more than 5 percent consistently is worth closing. Common culprits are cloud sync services like OneDrive or Google Drive, antivirus scans, and browser extensions. Disable startup programs you do not use daily: go to Settings > Apps > Startup and toggle off anything unnecessary. On macOS, check System Settings > General > Login Items and remove programs you do not need running at startup.
Turn off wireless and unused hardware features
Bluetooth, Wi-Fi, and USB devices draw power even when idle. If you use a wired ethernet connection, disable Wi-Fi when you are not moving the computer. On Windows, click the network icon in the system tray and toggle Wi-Fi off. On macOS, click the Wi-Fi icon in the menu bar. Bluetooth uses less power than Wi-Fi but still adds up over hours — disable it if you use a wired keyboard and mouse instead of wireless ones.
External devices like USB hubs, external drives, and printers consume power when connected, even if not actively in use. Unplug them when you are done working, or use a power strip with an on/off switch so you can cut power to multiple devices at once. A single external hard drive left plugged in 24/7 can add 10 to 20 dollars to your annual power bill.
Check your power supply efficiency and monitor actual power draw
A desktop's power supply converts wall power to the voltages your components need, and older supplies waste 20 to 30 percent of the power they draw. If your PC is more than seven years old, the power supply is likely 80 Plus Bronze rated or lower. Upgrading to an 80 Plus Gold or Platinum supply cuts wasted power by 5 to 10 percent of total draw — a meaningful saving if your system uses 500 watts or more.
To measure your actual power use, plug your desktop into a Kill-A-Watt meter (available for 15 to 25 dollars) and record the wattage during typical work, gaming, and sleep. Multiply the wattage by the hours per day you use it, divide by 1000, and multiply by your local electricity rate to see the monthly cost. This tells you whether changes are actually saving money. For laptops, check the power adapter wattage printed on the brick — a 65-watt charger means the system uses at most that much, though usually less during normal work.
Manage GPU and CPU performance settings for your workload
If you have a dedicated graphics card (NVIDIA or AMD), it runs at full power by default even when displaying a desktop. NVIDIA cards let you switch to integrated graphics for everyday work through the NVIDIA Control Panel — right-click the desktop, select NVIDIA Control Panel, go to 3D Settings > Manage 3D settings, and set "Power management mode" to "Prefer maximum performance" only for games, leaving other programs on integrated graphics. AMD cards have similar options in AMD Radeon Settings.
CPU performance can be limited without affecting responsiveness. In Windows, open Control Panel > Power Options > Change plan settings > Change advanced power settings, expand "Processor power management," and set "Maximum processor state" to 80 or 90 percent instead of 100 percent. This reduces clock speed slightly but is imperceptible for web browsing, email, and document work. Reserve 100 percent for gaming or video editing.
Upgrade your monitor if it is older than five years
Older LCD and LED monitors use 40 to 60 watts continuously, while modern displays use 20 to 35 watts for the same screen size. If you have a 24-inch monitor from 2018 or earlier, replacing it with a current model saves 15 to 25 watts — roughly 130 to 220 kilowatt-hours per year, or 15 to 30 dollars depending on your local rate. The payback period is typically two to four years, after which the new monitor saves money.
When shopping, look for the Energy Star label, which guarantees the monitor meets efficiency standards. Smaller screens (21 to 24 inches) use less power than larger ones, so downsizing if you do not need the extra space also reduces consumption. Matte screens use slightly less power than glossy ones because they do not require as much brightness to be readable.
Frequently Asked Questions
Will lowering brightness or using power-saving mode make my computer slower?
Brightness has no effect on speed. Power-saving mode reduces CPU clock speed slightly, but you will not notice the difference for web browsing, email, or document editing. Gaming and video editing may be 5 to 10 percent slower, so switch back to balanced mode for those tasks. The slowdown is far less noticeable than the power savings.
How much money can I actually save by changing these settings?
Savings depend on your electricity rate and how many hours per day you use your computer. A desktop using 300 watts that runs 8 hours daily costs roughly 20 to 30 dollars per month to operate. Reducing power draw by 30 percent saves 6 to 9 dollars monthly, or 70 to 110 dollars per year. Laptops save less in absolute dollars because they use less power overall, but the percentage savings is similar.
Is it better to shut down my computer or let it sleep?
Sleep uses far less power than running but more than shutdown. If you use your computer multiple times daily, sleep is better because shutdown and startup take time and use power. If you use it once daily, shutdown saves more. Most people benefit from sleep mode set to activate after 10 to 15 minutes of inactivity, with full shutdown at night.
Do screensavers save power?
No. Screensavers keep your display and CPU running, using more power than sleep mode. Modern displays do not suffer from burn-in, so screensavers are unnecessary. Disable them and rely on sleep mode instead.
Should I unplug my computer when I am not using it?
Unplugging saves the small amount of power used by the power supply itself when the computer is off — typically 1 to 3 watts. Over a year, this saves 10 to 30 dollars depending on your rate. A power strip with an on/off switch is more convenient than unplugging cables individually.