A Deeper Dive on Set-tops and Power Consumption

by Leslie Ellis // April 02 2012

Nothing like a TED quote to launch a deeper dive into recent news around energy-efficient set-top boxes.

It’s from Donald Sadoway, a Professor of Materials Chemistry at MIT, and it goes like this: “If we’re going to get this country out of its current energy situation, we can’t just conserve our way out. We can’t just drill our way out. We can’t bomb our way out. We’re going to do it the old-fashioned, American way. We’re going to invent our way out, working together.”

Ok, Donald. Like it. Very tech-patriotic.

Here’s the issue, when it comes to set-top boxes and energy consumption: Invention is underway to introduce light and deep sleep modes for new set-top boxes, which is great. I’d go so far as totally great. But, there exists a big (double-digit millions) backlog of deployed set-tops that went into homes long before technology options existed to lower energy consumption per device.

That means it’s a big numbers issue, say the engine room technologists focused on reducing power usage in CPE: A few watt hours per set-top box, times millions of them, is a big number.

Let’s look at some numbers. Here in my lab, the cable set-top draws 32 watts when on, 30 watts when off. An absolute worst-case scenario is the old-style HD-DVR, drawing 47 watts, 24 hours a day.

That older box can consume 1,128 watts per day, of which an estimated 282 watts involves the power associated with actually watching TV (assuming six hours/day of viewing.) The remaining 846 watts is used to receive guide data, authorizations, firmware updates, and other “back office” activities.

Contrast that with current model DVRs, drawing in the range of 28 watts, in service, and 22 watts when turned off – which cuts overall power consumption to 564 watts/day. That’s half the power consumption. Translation: On/off modes can make a very big difference.

From a dollars and cents perspective, let’s say power costs 12 cents per kilowatt hour (your mileage may vary.) That means the new, sleep-mode box burns about six cents per day, or, just under $25/year. (Double it for older boxes.)

So why not just ditch all those power-hungry deployed boxes, and flash cut to the  new, power-mode beauties?Sorry. It’s just not an option. Too expensive! Just as only some small, very-eco subset of us is motivated to replace the existing HDTV set with one that saves $70/year in power, so it is that no video service provider – cable, satellite or telco – is financially equipped to trash millions of deployed boxes.

Which brings us back to inventing our way out of the CPE power-draw issue. All together now!

This column originally appeared in the Platforms section of Multichannel News.