Sleep mode

"Sleep" mode is a low-power standby condition entered automatically after a set period of inactivity. With rebooting, the laptop notebook can "wake up" from its sleep.

*An integrated computer is a product combining the processor and display monitor in one case and draws power through a single cord.

+ A multifunction device is a product that acts as more than one device, combining many functions together, like copying, faxing, scanning, or printing.

Rule of Thumb for products with Low Standby Power
1 watt saved in standby power = $1.25 savings in lifetime energy costs*

* The sum of the discounted present values of future annual energy costs is the lifetime energy costs. Future electricity price trends and a discount rate of 3.0% are based on federal guidelines. For example, the average life of a monitor is 4 years in which it may be assumed to be in standby "sleep" mode of 6000 hours per year. If it is a low standby power monitor than it consumes 1 watt instead of 3 watts, thereby it saves 2 watts, which is $2.50 over the life of the monitor. Low power notebook computers and other energy compliant products have an ENERGY STAR® label.

Standby versus Sleep modes

All ENERGY STAR® labeled computers, monitors, and other energy compliant products differentiate between standby and sleep modes. Standby mode is when the hard disk powers down, the monitor switches off, and the open applications are stored in the RAM. The processor is not turned off and to activate the machine, any activity of the keyboard, mouse, or an incoming call is required which quickly restores the former state of the notebook. In sleep mode, also known as the hibernation mode, the settings are saved on the hard disk, the processor is turned off, and a soft boot (restart) is required to make the machine wake up from the sleeping state. Standby mode consumes more power than sleep mode.

How to identify products with Low Standby Power featuring sleep mode

Without the ENERGY STAR® label, the only way to identify is to measure it with a watt-meter. Nevertheless, certain clues identify such products:

• An external power supply, for example, cell phone chargers, power adapters, etc.
• A remote control, for example, TVs, VCRs, audio equipment, etc.
• A continuous digital display, for example, computer LCDs, laptop TFTs, etc.
• A rechargeable battery, for example, NiCd (Nickel-cadmium), NiMH (Nickel metal hydride), or Li-Ion (Lithium Ion).
• Devices that do not consume standby power are those with a switch that physically breaks the circuit.

Efficiency Recommendation for computers by the Department of Energy, USA

Note: Computers using networking capability, require the processor or memory to be involved during sleep mode. For such laptops, the recommended sleep mode is 15% of the maximum power supply rating.

Tips to use power efficiently

• Combining an external monitor or docking station with a laptop will increase power use.
• The "idle time" delay in the computer software should be set to the shortest time as per your needs, to save power. For example, you may like to set the laptop to go to sleep mode after 10 minutes of inactivity.
• Manually shut off the monitor, computer at night, on weekends, and during long periods of non-use during the day. This saves a lot of energy.
• If the computer is networked and has to remain on for the whole night, then switch off the monitor. You can also use special network features like timed shutdown, automatic shutdown, auto-boot-up etc. Using the sleep and off modes does not shorten the laptop notebook's lifetime.
• Laptop battery chargers use 15 watts or less but cannot be shut off completely. Hence, after the battery is fully charged, to save energy, the power supply should be unplugged.
• Web cam notebooks and wireless notebooks use more power. The features if not in use should be disabled to conserve power.