Carnegie Mellon University, PA "Sleep is Good" Initiative
What is "Sleep is Good"?
This is a Green Practices Initiative that is a simple way to save energy in one minute!
Our goal is to save 2 million kilowatt-hours (about $130,000 per year) through improved monitor management.
Reducing energy use by this amount is equivalent to:
- The energy used by 1,150 US Households during one month.
- CO2 reductions equal to preventing emissions from 140 cars.
- Planting 10 million square feet of trees.
Computers and monitors, especially CRT monitors, are significant consumers of electricity. On our campus, there are as many as 20,000 computers, most of which have monitors. Anytime this equipment is left on when not in use, it wastes electricity. Green Practices hopes to educate the campus community about saving energy through better computer and monitor management.
A 17-inch monitor uses 100 Watts of electricity on average, which is roughly equal to an incandescent light bulb. While 100 Watts is not an enormous amount of electricity, it does become significant if a monitor is left on all the time. Since electricity is measured and billed in kilowatt-hours, if you use a 100 Watt monitor for one hour, you use 0.1 kilowatt-hours of electricity. If left on all the time (8760 hours per year) the monitor would use 876 kWh. We pay an average of 5 cents per kilowatt-hour for electricity; therefore the monitor's energy consumption would cost approximately $44 for one year.
One easy and obvious way to reduce the amount of electricity wasted is to switch off the monitor when you leave for lunch or go home for the day. However, most operating systems have a simple setting that makes your computer turn off the monitor for you, after it has not been used for a set period of time. We have found that many monitors do not have the energy saver enabled, and those that do have it set for 30 minutes, while we recommend using a setting of 10 minutes. By decreasing the time you keep your monitor turned on, you increase the energy saved. On average, allowing your monitor to go to sleep reduces energy use of your desktop computer by 72%! You can verify or activate your sleep time setting by following these instructions.
Changing your power management settings by even just a few minutes has an impact on how much energy you save. While the amount may be small for your computer, perhaps only $5 per year, when you consider the 20,000 monitors on campus that would be $100,000 saved overall. Carnegie Mellon can then use that money toward great things on campus, such as speakers, events, or other green initiatives. Also remember that using less energy means you are saving resources and helping to reduce air pollution.