EfficientProducts.org | Set Top Boxes

When TVs were first introduced into the market, only an antenna was needed to view programming broadcast through the air. But over time, a number of other services have been introduced to supplement and expand the entertainment provided by broadcast TV, including video games, cable and satellite transmission, and video recording/playing devices. These “extra” services have evolved through the years but have always required a set top box (STB). With almost 70% of the TV-watching public in the U.S. subscribed to cable TV and millions more subscribed to other pay TV services[1], these devices have become essential to delivering entertainment and information. Unfortunately, this new and growing electricity end use is also frequently an example of inefficient design. Many STBs consume the same amount of power when turned on as they do when the user thinks they are turned off, consuming energy and costing money. Efficient Products.org focuses in on the category of STBs that currently has the largest energy consumption, cable/satellite STBs. Read on to find out more about STBs and what is being done to make them more efficient.

What do we mean when we say "set top box"?
The term STB can apply to any electronic device that is connected to a television. A majority of these boxes are designed to take a signal from a cable feed, satellite dish, broadcast antenna, or other source and convert it into a signal that can be viewed on a TV. These types of STBs range from simple converter devices all the way up to computer type boxes that are capable of displaying HDTV signals and incorporate digital video recorders (DVRs). Other STBs are designed to allow users to play video games (such as the X-box), or digitally record programming (e.g. TiVo™ boxes). STBs can be divided into several basic categories, also shown in the figure below. With each increase in product functionality also typically comes an increase in the power consumption and energy use of the STB:

Digital television adapter (DTA) – a form of STB designed to take broadcast digital TV signals and convert them into an analog format useable by analog TVs
Cable/satellite converter – a STB designed to convert digital or analog cable/satellite signals into digital or analog signals useable by a TV. Cable/satellite can also be used to descramble premium pay content on cable/satellite networks. This type of box is one focus of discussion on Efficient Products.org
Stand-alone Digital Video Recorders (DVRs) – STBs such as the TiVo™ that are designed to digitally record TV content for instant playback
Game Console – STB that allows the user to play video games, browse web pages or otherwise interact with audiovisual content displayed on a TV
Cable/Satellite Multi-function STBs – a form of cable/satellite converter that may contain a DVR, DVD recorder, multiple cable/satellite tuners, etc. This type of box is one focus of discussion on Efficient Products.org
Media PC – a personal computer designed to tune cable/satellite signals and that can display digital media content on a TV screen without the need for intermediary audio or video adapters

Note: DVD and VCR devices are typically categorized by themselves and are usually not included in the STB category.

How many cable/satellite set top boxes are in use and how much energy do they use?
An estimated 90% of American households get their TV from cable or satellite sources[2], and if you live in one of these households, chances are you need to connect a STB to your TV. The American Council for an Energy-Efficient Economy (ACEEE) estimates that, in 2003, the U.S. had a total of 67 million cable/satellite STBs installed in homes. By 2010, ACEEE predicts that these numbers will swell to 107 million, as more and more households embrace the advent of digital television (DTV) and the TV-viewing population increases[3]. This does not even begin to cover the number of DTAs that might be used in the future to convert broadcast DTV signals for the millions of Americans that own analog TVs.

The energy use of a cable/satellite STB can vary widely with the functionality of the box. Today’s basic cable/satellite boxes that are designed for compatibility with analog TVs consume about 150 kilowatt hours (kWh) of electricity per year – similar to the amount that a computer monitor might use – whereas multi-function cable/satellite DVR boxes could use over twice as much – closer to the amount that an energy-efficient washing machine might use and costing in excess of $20 per year in electric bills. Combine these numbers with a modest sampling of other home entertainment equipment that Americans typically own, such as TVs and VCRs, and the resulting annual energy consumption approaches 1200 kWh per year or about 10% of the average American household’s electricity bill[4]!

Cable/satellite STBs alone consume over 13 billion kWh of electricity every year in the U.S., accounting for 1% of national residential electricity consumption and costing consumers over $1.1 billion in electric utility bills.

But energy consumption in cable/satellite STBs needn’t be this high. This type of box today can consume about as much electricity when they are turned off as when they are on so that even when the user turns the box off with a remote control, it continues to draw an almost identical amount of electricity from the wall outlet. The relative absence of low-power modes in today’s cable/satellite STBs represents a large opportunity for energy efficiency improvements and significant electricity savings.

How can I find today's most efficient cable/satellite set top boxes?
Identifying an efficient cable or satellite STB today is an extremely difficult task, mainly because there aren’t any labeling or promotional programs related to energy consumption and efficiency for these products. Furthermore, as a consumer, you may have little choice in the brand or model of cable/satellite STB that is installed in your home. Very often, that is decided by your TV content provider.

What is a TV watcher to do? Fortunately, EfficientProducts.org has a few tips that can keep your current STB running as efficiently as possible and will help to identify important energy-saving features in future boxes:

What is the definition of efficiency for cable/satellite STBs?
Efficiency advocates have not yet agreed on a definition for cable/satellite STB efficiency. Current approaches toward characterizing efficiency in STBs look at power consumption in different modes of operation. For example, one might measure the power consumed by a DVR-style STB when it is on and recording a program. However, due to the ever-increasing array of features offered in cable/satellite STBs today, it is extremely difficult to define a set of universal operation modes that can apply to this very diverse category of devices.

Currently the simplest and most readily understandable measure of STB efficiency is its estimated annual energy consumption, expressed in kWh of electricity.

Is there a way to test efficiency?
As mentioned above, disagreements over the definition of universal operational modes in STBs have slowed the process of both defining efficiency and establishing a test protocol to measure it.