Use ENERGY STAR®-rated equipment, which consumes up to 50% less energy than standard models. Set equipment like printers and scanners to automatically switch to sleep or energy-saver mode when not in use. In addition to saving energy, the equipment will stay cooler, which will help extend its life. Another way to save energy in your home office is to use efficient lamps for task lighting. Replace any older bulbs with energy-saving LEDs.

Source: energy.gov