Consumer electronics, office equipment and other plug loads consume 15 to 20 percent of total residential and commercial electricity in the United States. Much of this energy is consumed when these devices operate in low-power modes but are not actually in use. One way to reduce this unnecessary electricity consumption is to use smart plug strips.
By automatically turning off plug loads when not in use, smart plug strips can provide energy savings in homes and offices. Applications for smart plug strips include workstations, open office cubicles, home offices, and home entertainment systems. Estimates of exactly how much energy can be saved with smart plug strips vary, and are highly dependent on the type of smart plug strip used, which devices are connected to the smart plug strip and how the devices are connected to the smart plug strip.
What do we mean when we say "smart plug strip"?
Smart plug strips look similar to typical plug strips, but also incorporate additional technologies to automatically disconnect power to certain equipment when not in use. Most smart plugs strip have one “master” control outlet, four to six controlled outlets that will automatically power down designated devices, and one or two uncontrolled outlets that are always on. Smart plug strips vary in design, but typically employ occupancy sensors, load sensors, remote controls, timers or USB interfaces to automatically power down plug loads when they are not in use.
Occupancy sensing plug strips detect the presence or absence of a person, and automatically turn equipment on and off accordingly. These smart plug strips usually have one or two outlets that are always on, meaning that they remain constantly powered and are not affected by the occupancy sensor.
Load sensing smart plug strips detect the drop in current that occurs when the control device enters a low-power mode. For example, if the control device is a computer, the load sensor would detect when the computer enters sleep or standby mode, and then disconnect power to the other devices plugged into the strip.
Some smart plug strips use wireless remote controls. The advantage of the remote control smart plug strip is that it is a convenient way to control exactly when devices receive power or don’t without having to reach below desks, behind home entertainment equipment, or around furniture to access inconvenient places where plug strips are typically located.
Smart plug strips can also turn equipment on and off based on a programmable timer. Turning devices on and off with a timer ensures energy savings over night, and on weekends and holidays.
Smart plug strips using USB interfaces plug into the computer via a USB connection. When the computer goes to sleep or is turned off, a signal from the USB port shuts down the flow of power to peripherals (e.g. printers, scanners, modems, speakers, and standby lights).
How many smart plug strips are in use and how much energy do they save?
Little independent market research information is available on smart plug strips. Existing research suggests the stock of smart plug strips to be small. However, there is increasing interest in smart plug strips and many manufacturers now offer these products.
Estimates of exactly how much energy can be saved with smart plug strips vary, and are highly dependent on:
Our preliminary research suggests that a smart plug strip used with office equipment (at home or at work) can save from 25 to 180 kWh per year and that a smart plug strip used with home entertainment equipment like TVs, DVDs, and amplifiers can save from 25 to well over 100 kWh per year.
How can I find the best smart plug strips?
Each smart plug strip technology has advantages and limitations. The energy that will be saved is highly dependent upon the application. It is helpful to think about how and when the smart plug strip will be used before choosing a product.
Where will the plug strip be installed? Power or current sensing smart plug strips work well in home offices and home entertainment centers where there is a central device (TV or computer) and several peripheral devices (printers, DVD players, speakers) that are used only when the central device is on. Occupancy sensor smart plug strips can work well in office cubicles because they can detect the presence or absence of the office worker and turn devices on and off accordingly. A timer smart plug strip could be used on devices that never need to operate during certain hours. Examples include office equipment such as printers and home entertainment equipment like stereos.
Who will be interacting with the smart plug strip? Remote control advanced plug strips can achieve energy saving in many settings, but the people who use the equipment must remember to also use the advanced plug strip remote control to turn the strip on and off when appropriate. Occupancy sensors will be triggered by motion from anyone in their detection zone. An area that people enter for multiple reasons- not just to use the designated equipment- may be better suited to a different technology. Timer advanced plug strips are appropriate in situations where schedules are consistent.
Additional considerations are:
Pick a product with an adjustable time delay. smart power strip products may come with either adjustable or manufacturer-set time delays that determine how long a period of non-occupancy or inactivity must be before the equipment is turned off. A product with an adjustable time delay allows adjustment of the smart power strips to suit individual habits.
Pick a product with low power demand. smart plug strips draw a small amount of power by themselves. Our testing showed that smart plug strips draw between 0.004 and 1.8 watts when no devices are plugged into them. While energy savings will typically outweigh any energy consumed by the smart plug strips, it is important to note that some smart plug strips use a small amount of energy themselves.
Smart plug strips are available in stores and online at many electronics retailers. They go by many different names, including:
Smart plug strips
Energy Savings Power Strip
Energy Saving Surge Strip
Smart Power Surge Strip
Smart Surge Block
AutoPowerOff Plug Banks
Advanced Power Strips
Is there a way to measure the energy savings from smart plug strip?
At present, little independent research exists that verifies energy savings from smart plug strips. Ecova (Formerly Ecos) recently completed an smart plug strip research report that provides a technology overview as well as preliminary savings estimates. We hope to conduct large scale plug load field monitoring studies using a variety smart plug strips in different settings soon. Because smart plug strips savings are highly dependent on field installation conditions, this data would very useful for more detailed predictions of the amount of savings that can be realized for individual applications.