How Much Energy Is Being Wasted?

Irvine, CA, May 8, 2015 -- If you think you’ve set your office desktop computer to automatically slip into sleep mode at night and on weekends – ensuring you’re doing your part to curb fossil fuel consumption – you’re probably wrong. And you aren’t alone.

Calplug researchers Joy Pixley and Stuart Ross found desktop computers may use more energy than we think.

At least that’s what a pair of studies, conducted by the California Plug Load Research Center (CalPlug) and sponsored by the California Energy Commission, has determined. Contrary to what users may believe, computers are not entering sleep mode or automatically turning off as often as expected, and they’re consuming more energy than most of us realize.

Last month, the California Energy Commission released proposed new standards for computers and monitors, influenced by findings from the CalPlug and other studies.

The commission wants the power used by idle desktop computers to be reduced by 50 percent, and power management features to be improved, starting in 2018. The CEC estimates the proposed changes would save 2,702 gigawatt hours a year, potentially reducing utility bills of consumers by $430 million annually.

A recent Washington Post story suggested that CEC’s proposed groundbreaking standards could become a blueprint for the nation, “given the size of its (California) population and market and also the presence of key parts of the tech community within the state.”

Register now to attend California Plug Load Research Center’s 7th semiannual workshop on energy efficient plug loads. Tuesday, May 12, 2015 at the Calit2 auditorium. for more information, and to register online click here.


CalPlug researchers Joy Pixley, project manager for social sciences, and Stuart Ross, a policy analyst, conducted the extensive studies on computer power management and user behavior.

Their online survey in 2013 gathered detailed usage data on more than 3,000 office and home desktop and laptop computers from 2,081 UC Irvine students, staff, faculty and retirees. Last year they followed up by examining the actual power-management settings of 125 of the participants’ office desktops, and remotely monitoring the power states of 119 of them for about one month.

The studies indicated most users are not enabling automatic power-management settings correctly.

Computer power management (PM) – the act of switching a computer to sleep, hibernation, or shutdown mode – can be activated manually or automatically.

Automatic PM is a built-in ENERGY STAR® feature designed to reduce energy use. However automatic PM can be disabled, or in some cases never enabled. A 2010 report from the Consumer Electronics Association estimated that 30 percent of home computers have power management disabled.

Desktop computers can use 60-300 watts of power a day when they are turned on, but energy consumption typically drops to less than five watts when PCs are in sleep mode.

And because computers and their monitors account for nearly six percent of California’s residential and commercial-sector electricity use, the California Energy Commission wanted to determine whether users were taking advantage of PM options. “The information from this study will be used to consider future regulations and programs to improve enabling rates in computers,” says Laurie ten Hope, CEC deputy director, Energy Research and Development Division.

While previous studies projected possible energy savings from PM for selected computer models, this was the first large-scale study designed to examine users’ behaviors toward manual and automatic power management. “We wanted to focus just on the behavioral aspects, how and why people relate to their power management situations,” Ross says.

Findings included statistics about the number and types of computers participants reported manually shutting down or putting into sleep mode, the percentage of participants from various groups who have changed their power settings, behavior differences between desktop and laptop computer users, and the average amount of time per week office desktop computers are in specific power modes.


The findings are consistent with the idea that users are confused about power-management settings, and wrong about the amount of energy they believe they are saving, Pixley says. An especially large gap emerged between what people said their office desktop computer power-management settings were and how many computers were actually using those energy-saving features. While participants reported enabling automatic PM on a 84 percent of office desktops, monitoring in the second study confirmed this to be true for only 20 percent.

Participants were anonymous, but several shared comments about their user behavior and the survey. “Made me realize how much I leave my computer on when I'm not using it, and that I should change the settings to better fit my lifestyle at the moment,” one respondent commented. Another added, “I always turn off my monitor to save energy when I leave my office, but I did not know how to hibernate the office computer so I can still access it from off campus -- if there is a way to do that, I would happily save more energy.”


“It’s not enough to tell people they should save energy.  We need to address the reasons why more people aren’t using low-power modes, whether it’s technological problems or confusion about office policy or just forgetting.  Make it easier to use sleep mode, and more people will use sleep mode,” Pixley says.

The university recently installed new software that will allow better control and customization of power-settings on office desktop computers, says Jeremy Paje, manager, Standard Desktop Support with the Office of Information Technology (OIT).
The next step is to determine how restrictive the power management profile settings should be for the nearly 2,000 office desktop computers supported by OIT. They will also identify departments that need to be exempt, such as facility’s central plant and UCI police dispatch, because they require uninterrupted, 24/7 computer operations.
 “Even if we implemented the least restrictive power setting (set computer for standby/sleep mode on weekends), the university would save more than $22,000 a year,” Paje says. “And the reduction in carbon emissions would be the equivalent of taking 34 cars off the road.”

The CalPlug studies were published by the California Energy Commission and can be viewed online at: and


Users give a variety of reasons for not enabling energy-saving, power-management features on their computers. Here are a few common myths identified by

MYTH: More energy is saved by manually shutting down a computer than by enabling automatic PM settings.
REALITY: Turning the computer off does save a few watts compared to automatically transitioning to sleep mode, but forgetting to shut down a computer a few times could negate a year’s worth of energy savings.

MYTH: Putting computers in and out of sleep mode several times a day will decrease their life span.
REALITY: Most computers can handle up to 40,000 on-off cycles before failure. Some studies show it would require cycling on and off every five minutes to damage a hard drive.

MYTH: If the computer is sleeping, it can’t automatically receive important software updates.
REALITY: There are several ways to ensure that software updates are applied, including waking up computers automatically through the network prior to distributing updates.

MYTH: Because most manufacturers now ship computers with automatic power management already enabled, there is no need to check automatic settings.  
REALITY: Default computer settings are often changed by computer resellers, third-party service providers, or IT departments before end users acquire them.

MYTH: Computers and monitors use more energy with power-management settings activated, due to power surges when cycling on and off.
REALITY: The small surge of power created when computers are turned on is far smaller than the energy used by running the device when it is not needed.


Another common misconception involves computer monitors. Even if your monitor goes dark when the computer is not being used, the computer might not be set to enter sleep mode; this requires an extra step. Pixley and Ross say they believe survey respondents may have thought their computer was asleep when only the monitor was off. Both Windows and Apple computers allow users to set the amount of idle time that occurs before the device goes into standby or sleep mode.
To view instructions on how to activate power management on your computer, visit