A Deeper Dive on Set-Tops, Power Use


a deeper dive into recent news
around energy-efficient set-top

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 backlog (in
the double-digit millions) of deployed set-tops that
went into homes long before technology options
existed to reduce per-device energy consumption.

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.

Which is why the recent news about sleep
modes (http://bit.ly/HgMuwV) is such a big step
in the right direction.

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 for 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-offi ce”

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
$22 per year. (Double it for older boxes.)

So why not just ditch all those power-hungry
deployed boxes, and flash cut to the new, powermode
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!

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