FA info icon.svg Angle down icon.svg Project data
Type Green IT
Authors Matthew Urquhart
Location Kingston, Canada
Status Verified
Verified by Queen's University Green IT Group
Uses saving energy
OKH Manifest Download

Download ECM now!

Standby power or "phantom power" is defined as the power consumed by electric and electronic devices, such as computers and television sets, when they are plugged in but not performing their desired task, even if they are not turned on. This power consumption has been quantified as representing more than $3 billion in annual energy costs in the continental United States.[1] Much of this cost is avoidable in both residential and commercial applications through the use of "smart strip" power bars.

Smart strips[edit | edit source]

Smart strip power bars replace traditional power bars and have one control device that will switch power on/off to the other devices on the strip. For example, at a typical workstation you may have a computer (monitor and CPU), a phone charger, a desk lamp, a printer/scanner/copier, and perhaps some speakers. It is our recommendation that the computer's CPU (or whichever device is regarded as most critical) be the 'control' device, such that when you power down your computer at night and turn the CPU off (that is, pushing the power button to turn it off, but leaving it plugged in), all power going to the remaining devices is cut completely; the CPU will still draw its phantom power, but the remaining devices will draw no power. It is for this reason that all of the phantom power will not be eliminated, but a significant portion of it will be reduced.

ECM inputs[edit | edit source]

Note that some of these values are classified as 'inputs' (to be changed by the user), while others are 'defaults' (may be changed by user, but original values are relatively inert to type of organization, location, etc.). Be sure to enter numbers and responses carefully as the quality of the inputs determines the quality of the responses the calculator will provide.

  • Information about current power bars (price, number of outlets, etc.)
  • Information about replacement power bars, smart strips (price, number of outlets, percentage reduction in phantom power, etc.)
  • Labour to change power bars (cost and duration)
  • Energy grid information (on- and off-peak pricing, grid emissions)
  • Decision as to whether power bars need to be replaced now anyways (i.e. expiration of warranty for surge protection), or not. This is answered as a "Yes/No" question.
  • Information about the devices used by your organization (type, number of devices, average standby consumption, hours of use) with room for expansion by user.

ECM assumptions[edit | edit source]

You are strongly encouraged to review all assumptions on which this calculator is built before carrying out the analysis for your organization. Care was used in the development of this calculator to ensure its robustness, however some of its features may not be applicable to your organization. A sample of the assumptions used are listed here,

  • Heavy users of electricity, such as refrigerators or air conditioners, should not be plugged into power bars.
  • The difference between seemingly similar devices can be substantial. Do not discount a device on intuition alone, as actual electricity consumption can be surprising, especially when considered for large organizations.
  • Only devices that were previously plugged into conventional power bars are to be plugged into new power bars. That is, no additional devices or behavioral changes were taken into account.
  • Average values for a class of device are provided by default (from[1]) but should be updated to the particular usage of your devices if possible.
  • The particular 'power state' of the device is important in determining energy consumption (i.e. compare 'on', 'off' and 'standby' power consumption). Similarly, the mode by which the device was moved to that power state may affect its power consumption (i.e. using the remote to turn off the TV, rather than pushing the button on the device itself.)
  • Geographic location is initially set to Kingston, Ontario. If you're location differs, you may need to adjust the cost of electricity and the grid emission mixture (sources are provided).

Download this calculator[edit | edit source]

The most recent version of this calculator, as confirmed by the Queen's Green IT Group (original constructors of the document), is available here:

See also[edit | edit source]

For more information, check the Queen's Green IT ECM homepage, at Category:Queens Green IT ECMs

Related Research Page: Phantom power reducing power bars

References[edit | edit source]

Cookies help us deliver our services. By using our services, you agree to our use of cookies.