Pity the poor cable box. It’s a constant family room reminder of multichannel monopolies and oppressive bills. We love to loathe it for delivering hundreds of channels with nothing on, and yet many of us can’t live without it. Legions of others have cut its cord in favor of streaming services that deliver shows from the web to the tube, tablet or PC. Yet there it is, workmanlike in our A/V racks and stacks, operating 24/7 and delivering related services like digital video recording (DVR).

And that creates another problem. The always-on cable set-top box has recently been targeted as a chief energy hog, on the household hit list for inefficiency and waste. It’s been chided and derided by the Natural Resources Defense Council (NRDC), which last year reported that the average new cable or satellite box with a high-definition digital video recorder (HD DVR) consumes more electricity annually than a new flat panel TV and more than half the energy of an average new refrigerator.

The set-top box just can’t win, it seems.

CableLabs and set-top box chip maker Broadcom are out to change that image. CableLabs has promised boxes that save energy by going into “light sleep” modes by September, and Broadcom says set-top boxes with its new energy-saving chipsets should be available by then.

“The set-top box is a network device that supplies 100 percent network communications 24/7, but they are power-intensive boxes and shame on us for not paying better attention to that,” admits Joseph Del Rio, product line director with Broadcom’s Broadband Communications Group.

In the brave new world of home connectivity, making a set-top box energy-efficient becomes both a challenge and a necessity, as many set-top boxes will serve as gateways into the home not just for hundreds of video channels, but for Internet services, VoIP phone and networking—all features that require more energy and 24/7 network readiness.

In light of this, Broadcom’s new BCM7425VMS chip set can allow for four different power states, programmable by the cable or satellite operator or hardware vendor:

• On—All functions operating.
• Active Standby—Turns off video, stops processing engines, turns off part of transport path and maybe transmitters.
• Low-Latency Standby—The microprocessor shuts down other functions, and may result in slight delay when resuming power.
• Deep Standby—Also known as “deep sleep,” in which almost everything is shut down, the CPU is in a halted state and almost all DOCSIS (Data Over Cable Service Interface Specification) channels are shut down, except one to handle updates or VoIP phone calls.

Del Rio says demonstrations show set-top boxes in Deep Standby can consume less than half a watt of electricity and can resume full active video decoding in 4 seconds, while other functions like Video on Demand will take longer to restart.

Deep sleep has been promoted by the EPA’s Energy Star program that certifies energy-efficient set-top boxes and other electronics and appliances. Deep Sleep is a part of Energy Star’s current 3.0 specification for set-top boxes and the 4.0 (now likely 4.1) spec that will go into effect in July 2013, but it is not mandated by either. According to the EPA, only two of 57 set-top boxes that qualify as Energy Star offered Deep Sleep as of April.

“In the old days, the video would turn off,” says Del Rio. “Now we can shut down the CPU and graphics, turn down the DVR,” and bring back basic video functionality while other functions take more time to reboot.

Rise of Thin Clients?

Del Rio also touts the use of thin clients as secondary devices in other rooms and connected to the main set-top box or gateway by Ethernet cable or coax. These can save energy by concentrating tuner and DVR functions in the main set-top box and only coming on when needed. MoCA (Multimedia Over Coax Alliance) technology provides wakeup on LAN (local area network) functionality for this. The use of thin clients have also been promoted by Energy Star.

“Why have a full, complete set-top box with tuners in every room,” says Del Rio, “when you can aggregate tuning through one device in the home and save power for the entire home.”

Broadcom says it is putting some intelligence in the set-top box to monitor itself so it can dial back power, based on what the user is doing.

Future Services

It all sounds so nice, but these are big bad set-top boxes, remember, distributed widely by big bad cable companies with their oppressive bills and nothing-is-on services. Questions are bound to abound, such as whether cable and satellite operators will use Deep Standby or deep sleep modes, especially if they are not mandated under Energy Star guidelines.

“We are discussing a path for deep sleep for [the revised 4.1 spec] now,” says Katharine Kaplan of the Energy Star program. “In order for it to be mandatory it must have some play in the market. That is not true yet. We are looking for ways to incent the uptake in the market.”

It appears that the set-top box has arrived at a crossroads, requiring it to provide more connected home functionality and network readiness, while at the same time curbing its energy use. In the near future set-top boxes could also serve as home gateways for digital health care, home security and energy management services. Multichannel service providers Comcast, Verizon, Time Warner and now AT&T are trying to sell all manner of basic home connectivity and wireless control services that could eventually tether to the set-top box. If it’s still around.

“As more services move into the cloud, that’s another area for saving power in the home,” says the optimistic Del Rio. “But [with more cloud-based services], it becomes even more paramount to be connected more reliably than before.”

Steven Castle - Contributing Writer

Steven Castle is Electronic House's managing editor. he has been writing about consumer electronics, homes and energy efficiency topics for two decades. He is also the co-founder of GreenTech Advocates.