Turn off unused work computers at night

Sustainability Challenge
This challenge is worth 1 YouSustain Award () each time it is completed.


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Length: 7 days.
Associated with: Conservation and Efficiency
A lot of people have started being careful about energy use at home but don't think about it at work. The reason is simple: we're not paying for the electricity. However, the electricity we use (and waste) at work still ends up emitting CO2.

Many people leave their work PC running 24/7. Unless there's a reason for this (running as some kind of server) this is completely unnecessary.


  • Set your computer to automatically go into sleep or stand-by mode after being idle for say 30 or 45 minutes. It only takes a few seconds for a computer to wake from stand-by mode. While in stand-by mode the computer will use only about 1-2% of the electricity used while turned on.
  • Monitors set to use a screensaver don't use any less electricity than when turned on.

Savings Calculation

An average PC will use about 100 watts when sitting idle. The average monitor in businesses today is probably a mix between CRT (80 watts) and LCD (35 watts) so we will use 60 watts.

Assuming an 8-hour work day for 5 days a week, then 2 full weekend days, that's 128 hours of idle time per week and 6656 hours per year.

160 watts x 6656 hours = 1064 kWh

The average CO2 emissions per kWh is 0.7kg, so that gives 745kg/year, and 14kg/week for this challenge.

Since this challenge is for a work computer it assumes no personal cash savings.


The estimated impact each time this challenge is completed: 14 kg / 31 lbs CO2 reduced and saving up to $0!
All completions of this challenge have reduced approximately 18.03 tons CO2 and saved up to $0!

Administrative Details

Current members: 275
Created: 2007-12-17 18:12:07
Administrators: NeilT
Sustainability Challenge
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