[ 2] Phantom power (standby power, idle current, vampire power, and wall warts) refers to power consumed by electronic devices when they are switched off, in standby mode, or are otherwise consuming electricity without performing any useful function requiring power. Three to 10 percent of residential electricity is attributed to standby power, according to recent estimates. Bertoldi, P. et al. “Standby Power Use: How Big is the Problem? What Policies and Technical Solutions Can Address It?” Proceedings of the 2002 ACEEE Summer Study on Energy Efficiency in Buildings. (2002).

[ 3] http://www.potenco. com

[ 4] The XO,which has been referred to as the “$100 Laptop,” is an inexpensive laptop computer designed and distributed by the One Laptop Per Child (OLPC) organization for children in developing countries around the world.

[ 5] According to the OLPC website, the XO “consumes less than two watts—less than one-tenth of what a standard laptop consumes.” http:// laptop.org/laptop/hard-ware/ highlights.shtml

[ 6] Gyllensward, M., Gustafsson, A., and M. Bang. “Visualizing Energy Consumption of Radiators” In Persuasive Technology. Berlin: Springer Berlin / Heidelberg, 2006.

[ 7] Verbeek, Peter-Paul. What Things Do: Philosophical Reflections On Technology, Agency, And Design. University Park, PA: Penn State University Press, 2005. Verbeek proposes transparency and engagement as design strategies for improving the material aesthetics of products in order to facilitate product attachment.

[ 8] http://www.tii.se/ static/ curtain.htm

while the other designs more radically redefine the user experience with respect to energy.

The Belkin Conserve power strip can be turned on and off via a large wireless-remote switch. It is primarily through its usefulness and usability that it encourages energy-saving behavior. For functional and aesthetic reasons, people typically place power strips out of view and out of reach. Consequently, many devices stay on because the on/ off switch is hard to reach. The Conserve offers convenience: The simplicity of the switch’s operation and form combine to encourage its use. It also provides useful and usable functionality for the user who is not conservation-minded. For example, anyone may find it useful to be able to remotely turn off his or her lamp at night. In doing so, other devices plugged into the Conserve may be turned off at the same time, regardless of whether the individual is aware of it. Hence, the person may not realize she or he is saving energy by turning off lamps and other devices that may be consuming phantom power [ 2]. Because the Conserve is a functional, logical combination of light switch and power strip, it seems unlikely to gain symbolic value or stimulate critical reflection about energy or sustainability. Rather, it will more likely be integrated into daily routines without actually raising awareness of the potentials for increased sustainability of use. The Conserve is useful and accessible to everyone, including those with physical disabilities. Through its functionality the Conserve gives more control back to its owner, who will likely use it in sustain-

able ways (whether or not she or he cares about sustainability).

According to the Potenco website, “a minute of pulling the PCG generates enough energy for 20 minutes of talk time on a mobile phone, one hour of ultrabright LED flashlight use, [and] three hours’ play time on an iPod Shuffle [ 3].” The Potenco Pull-Cord Generator (PGC) was specifically designed for use with the XO laptop [ 4]. It does not provide explicitly persuasive information, but because it is useful and convenient to remotely power digital devices by hand, it encourages hand powering rather than plugging in. The cost of energy is made immediate and tangible. As a result, one is more likely to conserve energy by shutting down devices when not in use. Moreover, it may be preferable to downgrade to extremely low-power devices such as the XO because the PCG does not generate enough energy to power a standard laptop [ 5]. In the case of the XO, nice-to-have functionality is sacrificed for the most essential functionality, along with the comfort and satisfaction of knowing that one’s bodily power alone can sustain it. Regularly engaging with the PCG may create an intimate relationship between the individuals, their devices, and their energy. A certain delight results from the playful interaction and the immediate feedback of watching a device come to life from your own power. The PCG seems likely to evolve symbolic value through use, representing self-sufficiency and sustainability. The PCG raises critical questions about what we truly need and desire from our digital devices. The PCG and XO were designed

for the developing world, which lacks reliable access to electrical power, yet people in the first world also desire these products. Many products we use in our daily lives assume an abundance of cheap energy, which invites unrestricted use without thought of harm. The Potenco PCG can make people aware of the human energy required to power electric devices, prompting thoughtful use.

The Element is an adjustable electric radiator constructed from 35 60-watt incandescent lightbulbs, which provide the heat source; the light emitted is directly related to the amount of heat produced and energy consumed. The designers note that “direct feedback…[may]… help consumers build conceptual models of how energy-consuming devices behave in different situations making the perception of electricity less abstract [ 6].” The visual feedback from the lightbulbs provides information that may help users better understand how the radiator works at an engineering level. For example, over time one may notice that cranking the thermostat setting all the way up does not cause the lights to glow brighter more quickly (since a thermostat is actually a switch, not a valve). The user may possibly make this connection and change her or his behavior by setting the dial to the desired temperature, rather than overcompensating, thus saving energy. This feedback can also act as a persuasive prompt. During user studies conducted by the designers, “some participants said [the Element] would be useful as an indicator of changes in the domestic climate such as open windows and function as