Monitor FAQs

What’s the big deal about energy efficient computer monitors?

Those of us who leave our computer monitors on, instead of in “sleep” mode, contribute to the more than $1 billion in annual energy costs in the U.S. associated with monitor use.  We also create approximately 15 billion pounds of greenhouse gases, which is equal to the emissions of more than 1 million cars.

Monitor manufacturers have made huge strides in creating energy efficient displays in recent years.  Still, for many buyers it’s challenging to find the most efficient models available.  To help you make the best choice for your family and the earth, TopTen took an in-depth look at the market for computer monitors.  The most relevant information is located here, including our criteria for selecting the ten most efficient products.

Where do we get our info?

Energy Star, the Natural Resources Defense Council, the California Energy Commission and various professional reports provided valuable information about the computer monitors listed at TopTen.  For a complete bibliography, read How We Evaluate.  Resources are listed at the end of that page.

How do we decide which computer monitors to include?

The ENERGY STAR database lists 469 computer monitors.  We only considered monitors that use less than 108 watts while in “on” mode for TopTen evaluation and separated this list into two categories based on diagonal screen size:

  • Small : up to 20 inches
  • Large: bigger than 20 inches

TopTen database includes information about monitors with the highest energy efficiency in each size category.

Why do some products have more than one model name?

Throughout the Energy Star database, we found two or more different models of the same size, resolution, and display technology from the same manufacturer listed separately, even though their total energy consumption values are quite similar or identical.  Sometimes model names change from one year to the next.  Manufacturers also create different model names to distinguish computer monitors with cosmetic differences, or other minor changes in features that do not have a meaningful impact on energy use.  To avoid multiple listings of the same product sold under different model numbers, we combined all such models into a single family of products, listing them only once, but providing a link to the other products within the same family under “similar models”.

How do we calculate cost savings? 

First, we created an efficiency index by dividing the screen area (inches) by power used in on mode (watts).  The monitor that can illuminate a given screen area for the smallest amount of power consumed is considered the most efficient.

Next, we compared the energy used by TopTen’s models to the average same size Energy Star model (kWh/year), which means that the savings are above monitors that are already considered energy efficient.  Multiplying the average kWh/year for each model by the average energy cost per kWh provides us with the average cost to operate the monitor each year.

Will I pay premium prices for energy efficient computer monitors?

Retail prices for products on the Top Ten list range from $xx- $xx 

What makes a computer monitor energy efficient?

Energy efficient computer monitors incorporate numerous energy-saving technologies and features.  These include: automatic brightness control, external power supply, LCD display, and LED backlighting.

  • Integrated into the monitor, Automatic Brightness Control saves energy by automatically adjusting the brightness of a display based upon ambient lighting conditions.
  • The external power supply converts the high voltage AC input from your electrical outlet to lower DC voltage(s) in order to powering the display.  Lower voltage power supplies use less energy than higher voltage supplies.
  • Old school computer monitors used Cathode Ray Tubes.  CRTs are both inefficient and contain toxic mercury.  Liquid Crystal Display (LCD): LCDs are the most popular type of television technology in use today.  They use a very bright fluorescent or LED backlight and millions of individual liquid crystals that can either absorb or transmit that light through individual red, blue, and green sub-pixels that together constitute individual pixels.
  • LED Backlighting:  LED backlighting uses less energy than fluorescent backlighting.  Backlights can be arranged in a full array behind the screen panel, or around the edges of the panel.  Edge lighting uses less energy than full array backlighting.