Current-sensing power bars reduce wasted energy - automatically


Poor computer energy management is probably costing your business. But here's the good news: you can do something about it.

Current-sensing power bars help reduce the energy use of all of the devices on or near a desktop, including desktop computers, monitors, printer, modems, cell phone chargers, calculators, desk heaters, fans, and even task lighting. They're easy to use, and a relatively inexpensive investment to help cut costs.

Eliminating phantom power loads

Almost every electronic device that's plugged into an outlet — even if it's turned off — is drawing power. That means most devices are using energy 24 hours a day, 365 days a year. In addition to these "phantom loads," at least 40% of workers in B.C. leave their computers and peripherals on while they are away from their desks. While seemingly small, these power draws quickly add up. Idling energy, combined with phantom loads, wastes an estimated $30-million worth of energy each year in this province alone. That's roughly enough energy to power 34,000 B.C. homes!

Changing entrenched workplace behaviour can be the most difficult hurdle when looking to reduce idling loads. When used properly, current-sensing power bars help manage these unnecessary energy draws, without requiring action from employees, by automatically shutting off devices when they are idle.

How current sensing power bars work

Current sensing, or "smart" power bars combine an electrical current sensor with a power strip and surge protection. They are designed to control the power draw from devices that can be turned off when not in use, including calculators, computer monitors, space heaters and printers. They also have "constant hot" outlets to accommodate devices that must stay on, such as cordless phones and modems.

Most models have seven to ten outlets. There is typically one "control" outlet, a number of others that are "controlled" outlets and a few more — often marked in red — called "always-on" or "constant hot" outlets.

"Smart" power bars work by sensing the current difference when the device in the control outlet is not in use, they will then shut down the control outlet and all the controlled outlets, leaving only the devices in the "always on" outlets running. Using the power bar at a typical workstation, with a computer and task light, can save about 100 kilowatt hours of energy per year.

Using smart power bars effectively

The best way to set smart power bars up for a desktop workspace is to plug the computer monitor into the control outlet. Then, use the controlled outlets for devices that are only required when the computer is in use, such as printers, scanners, and possibly task lights. As soon as the monitor goes to sleep (usually meaning the employee has stepped away from the desk), the power bar senses the change in current and shuts down all devices plugged into the controlled outlets.

Equipment that you want to leave on, such as a cordless telephone or modem, can be plugged into the always-on outlets.

When you return to the workstation, just a touch on your computer keyboard or a click on the mouse brings everything back to full power.

Shopping around

Smart power bars are increasingly available at stores that sell computer equipment and electronics. They generally cost between $15 and $30 more than a regular power bar, an expense that can soon be paid back in energy savings. But shop around — not all current-sensing power bars are equal. Read the labels to ensure the power bar itself draws no more than one watt when fully engaged and about a quarter of a watt when the controlled outlets are off.