Televisions and computers are typically dismissed as minor energy consumers in homes. But many homes have multiple TVs and digital decoders with personal video recorders (PVRs). In fact, in a study, researchers found that the TV decoder is actually your home’s second biggest power consumer, after your television (if it’s rear projection) when turned on.
According to a study by the Lawrence Berkeley National Laboratory, in a modern home, TV decoders and digital PVRs are the second biggest electricity-using appliance.
Such devices consume power both while switched on and while switched off. Although some standby power is used in these devices for features like clocks and remote-control operation, much or most of it is consumed by the appliances’ power supplies, which convert alternating current into direct current. However, because of their variety of functions, different appliances use significantly different amounts of power.
Incredibly, researchers found that decoders and PVRs use nearly as much power when they are off as when they are on–in some cases, it appears that switching them off with a remote control does nothing more than switch a light from green to red. The annual energy use of cable boxes ranges from 40 to 175 kWh per year, or about 120 kWh per year for the average model.
Satellite decoders consume even more power. Researchers found that decoders use from 11 to 21 watts while switched on and from 11 to 18 watts while switched off – which means satellite decoders use around 130 kWh per year.
Little can be done to cut the power use of set-top boxes. Unplugging is still an option, although this should be done with care. Some cable service providers issue dire warnings of service interruptions if their set-top boxes are unplugged.
For people who are leaving on a long vacation, unplugging all the TVs, VCRs, and set-top boxes seems like a sensible safety precaution–one that will also save money.
Source: Video Networks: A Surprising Energy Drain. The Home Performance Magazine.