Televisions
Product Definition/Scope of Product Category
Televisions (TVs) are electronic devices that display audiovisual content and that contain a built-in tuner capable of tuning off-air broadcasts. The presence of this tuner is what separates TVs from monitors.
The product definition also includes TVs able to display video signals from a computer (via RGB or DVI cable), TVs with build-in additional devices (e.g. DVD, Blu-ray Disc, Hard Disk Drive, VCR) and TVs composed of two or more separate components (e.g. separate display device and tuner) as long as they are marketed and sold to consumers primarily as televisions. Displays (products without tuners) that are marketed and sold to consumers as computer monitors or dual function television and computer monitors are not included at the present time, though they could be included at a future date if users are particularly seeking displays without tuners.
A variety of technologies can be used to create the image in TVs, including cathode-ray tube (CRT), plasma display panel (PDP), and liquid crystal display (LCD) in direct view models, and digital light processing (DLP), LCD, and LCOS (liquid crystal on silicon) technologies in rear-projection TVs. Organic light emitting diode (OLED) technologies may also reach the market in significant numbers in the future, but are not yet widely available.
Performance Criteria/Parameters Used
In developing the list of products that are eligible for TopTen USA, we evaluated products based on the following criteria:
Efficiency metric (square inches / watt). We determined efficiency on the basis of square inches of screen area per watt of power consumed. The TV that can illuminate the largest screen area for the smallest amount of power consumed is considered the most efficient. This is consistent with the current ENERGY STAR® approach.
Maximum power in active mode. We established an absolute power consumption limit of 90 W in active mode. TVs that use more than 90 W will not be listed on TopTen no matter how many square inches of screen area they are able to display. This is consistent with the approach taken by Topten in Europe (but more stringent) and ENERGY STAR v. 5.0 (not yet in effect).
Maximum power in sleep mode[1]. Power consumption shall be less than one watt in sleep mode. We did not give additional consideration to models with particularly low sleep power consumption; because the annual energy savings associated with reducing standby power levels by a fraction of a watt are not as large as the savings from reducing active mode power use.
Updates. We plan to update the performance criteria above on a quarterly schedule, as TV technology and product availability change. Most governments around the world have standardized a definition of television energy efficiency that relates active mode power consumption to screen area. The greatest area of remaining controversy in television efficiency metrics is what to do about screen brightness or luminance settings. Televisions with the highest claimed efficiencies may be achieving these readings through lower than average screen brightness. If true, such products might be adjusted by their purchasers to higher screen brightness settings in the home, therefore using more energy than claimed.
A number of approaches have been proposed to deal with the problem of screen brightness or luminance settings (see links at end of this document). The current ENERGY STAR version 4.1 specification requires that TVs operating in home mode achieve a certain minimum percentage of the luminance they deliver in retail mode. This specification took effect on May 1, 2010. Ecos is in the process of developing more specific recommendations on how to address luminance more effectively in future test procedures.
There are currently no federal standards or mandatory labeling requirements for TV energy efficiency, though both are in development. DOE has announced it will set the first-ever national standards for TVs by June 2013. The California Energy Commission established a mandatory minimum efficiency standard for televisions for sale in California beginning in 2011, with a second tier effective in 2013.
Test Methods
We used the following test methods for measuring the performance criteria listed above:
On Mode Power. IEC 62087:2008, Ed.2: Methods of Measurement for the Power Consumption of Audio, Video and Related Equipment, referenced in ENERGY STAR TV Program requirements versions 4.1 and 5.1 on p.10. For more information, see: http://www.energystar.gov/ia/partners/product_specs/program_reqs/tv_vcr_prog_req.pdf
Sleep Mode Power. IEC 62301:2005, Ed. 1.0: Household Electrical Appliances – Measurement of Standby Power, referenced in ENERGY STAR TV Program requirements versions 4.1 and 5.1 on p.10. For more information, see: http://www.energystar.gov/ia/partners/product_specs/program_reqs/tv_vcr_prog_req.pdf
Note that all products that offer extra features built into the TV should have these features deactivated during Sleep and On Mode power consumption testing. For example, during testing of TVs with built-in DVD players, a DVD disc is NOT inserted into the player.
Market Segmentation
We took the entire TV market and broke it down into three main categories based on reported diagonal screen size:
Small : 15 to 32 inches
Medium : >32 to <46 inches
Large: ≥46 inches
To ensure adequate representation of the entire TV market, we further divided each of these categories into two sub-categories based on reported diagonal screen size, rounding decimal values greater than or equal to 0.5 upward and values less than 0.5 downward. As shown in Table 1, for each of these sub-categories we listed the five most energy efficient televisions across the range of screen sizes available in that sub-category.
Table 1: TopTen Television Market Segmentation
|
|
Small (10 Models) |
Medium (10 Models) |
Large (10 Models) |
|||
| 15 to <27 |
27-32 |
> 32 to ≤37 |
>37 to <46 |
≥46 to <52 |
≥52 |
|
| Number of TopTen Models |
5 |
5 |
5 |
5 |
5 |
5 |
Data Sources
We used manufacturer reported data from the U.S. EPA ENERGY STAR website: http://downloads.energystar.gov/bi/qplist/tv_prod_list.xls
Based on our limited testing to date, the ENERGY STAR data on power consumption are generally conservative. A study conducted by Ecos in 2009 and 2010 showed that, in general, TV manufacturers report slightly higher power levels to ENERGY STAR than their products actually consume when tested according to ENERGY STAR’s procedure.[2] Only one of the 17 TVs tested consumed more power in home default mode than the manufacturer reported to ENERGY STAR. In future revisions of this list, we recommend testing samples of the models making the most ambitious energy efficiency claims to verify their performance and understand how screen luminance values may be affecting results.
Market Availability
In order to be qualified, the model must be currently listed on the manufacturer website and be available for online purchase.
Families of Similar Products
A number of examples are exhibited within the ENERGY STAR data set where two different models of the same size, resolution and display technology from the same manufacturer are listed separately, even though their total energy consumption values are quite similar or identical. This can result from model name changes from one year to the next or cosmetic differences in product housings 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.” For example, we allocated only one spot on the TopTen USA site for the 40 inch Sharp model LC-40LE810UN that had an annual energy use of 131 kWh/yr, and we did not include spots for models with similar performance that only differed due to the plastic finish color, base or addition of a feature that does not affect power use, such as the LC-40LE820UN. This similar model is, however, shown under “similar models.”
Product Ranking
Products are ranked according to their efficiency metric (square inches / watt). Models with an identical efficiency are ranked by size and, finally, alphabetically by brand name and model number.
Glossary
ENERGY STAR definitions
Luminance. The photometric measure of the luminous intensity per unit area of light traveling in a given direction. Luminance describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle. The standard unit for luminance is candela per square meter (cd/m2).
Off Mode. Where the product is connected to a mains power source and is not providing any On Mode or Sleep Mode functions, and where the mode may persist for an indefinite time. An indicator that only shows the user that the product is in the Off position is included within the classification of an Off Mode.
On Mode. Where the product is connected to a mains power source, has been activated and is providing one or more of its principal functions. The common terms “active”, “in-use” and “normal operation” also describe this mode. The power requirement in this mode is typically greater than the power requirement in Sleep and Download Acquisition Modes.
Sleep Mode. ENERGY STAR defines sleep mode, also sometimes referred to commonly as “Standby,” as the time when the product is connected to a power source, produces neither sound nor picture, neither transmits nor receives program information and/or data (excluding data transmitted to change the unit’s condition from Sleep Mode to On Mode), and is waiting to be switched to On Mode by a direct or indirect signal from the consumer, e.g., with the remote control.
Television. A commercially available electronic product designed primarily for the reception and display of audiovisual signals received from terrestrial, cable, satellite, Internet Protocol TV (IPTV), or other digital or analog sources. A TV consists of a tuner/receiver and a display encased in a single enclosure. The product usually relies upon a cathode-ray tube (CRT), liquid crystal display (LCD), plasma display, or other display technology. Televisions with computer capability (e.g., computer input port) may qualify [under ENERGY STAR’s] specification as long as they are marketed and sold to consumers primarily as televisions.
Other Definitions
Automatic Brightness Control. an integrated control system that automatically adjusts the brightness of a television based upon ambient lighting conditions.
Cathode Ray Tube (CRT). CRT TVs project an electron beam onto a phosphor coating inside a vacuum tube. This technology achieved significant gains in performance and energy efficiency over a period of more than 60 years, but is now largely obsolete. It has been displaced by flat panel designs for aesthetic and performance reasons.
Contrast Ratio. This is determined by dividing the measured luminance of 100 IRE (100% white) portion of a test image by the measured luminance of a 0 IRE portion of the same test image.
Digital Television (DTV). DTV is the industry’s term for a new standard in TV signals that is already transforming the TV landscape. Rather than representing TV pictures as an analog signal (like radio or standard broadcast TV), DTV transmits TV signals over the air and through wires as a series of digital ones and zeros. Congress required that broadcasters switch over to the digital format in 2009 - a process that was completed by most broadcasters prior to June 13, 2009.
Electricity Costs. Electricity cost is determined based on the following assumptions:
Product’s lifetime: 10 years
Usage pattern: daily 5 hours in On mode and 19 hours in Sleep mode
Tariff of electricity: $0.08/kWh - $0.18/kWh (this is based on the range of electricity rates by state in January 2011, published by the U. S. Energy Information Administration at: http://www.eia.doe.gov/cneaf/electricity/epm/table5_6_a.html)
High Definition Television (HDTV). HDTV is a new resolution format enabled by DTV that allows TVs to display widescreen images in high resolution (up to 1080 vertical lines of resolution or roughly triple the resolution of typical analog TVs). A TV that can display these images is called an HDTV. They have been the holy grail of home theater owners for some years now, but prices on HDTVs are coming down fast enough that even casual TV watchers are now purchasing these high performance TVs.
Liquid Crystal Display (LCD). LCDs are the most popular type of television technology in use today. They utilize 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.
Plasma Display Panel (PDP). Plasma TVs electrically excite the gas in individual cells to a plasma state, which then causes a phosphor coating to emit visible light. Contrast ratios, color quality, and off-axis brightness can all be quite good in PDPs, which has made them popular with video enthusiasts seeking relatively large screen sizes. However, they are more complex than LCDs, making it challenging for manufacturers to keep them cost competitive with LCDs in smaller screen sizes.
Rear-Projection TV. A type of TV whose display device is a projector that focuses images onto a screen located inside the TV enclosure.
Resolution. The physical pixel count for the horizontal and vertical axis.
Other Information
Key Publications
Assessment of Options for Improving Energy Efficiency Test Procedures for Displays
http://efficientproducts.org/reports/tvs/Ecos_Display%20Test%20Procedure%20Report_FINAL.pdf
Tuning In to Energy Efficiency: Prospects for Saving Energy in Televisions
http://www.efficientproducts.org/reports/tvs/NRDC_TV-4-pager_2005.pdf
NRDC report on TV Efficiency
http://www.efficientproducts.org/reports/tvs/NRDC_TV-efficiency_2005.pdf
Standards and Labels
ENERGY STAR TV Program Requirements http://www.energystar.gov/ia/partners/product_specs/program_reqs/tv_vcr_prog_req.pdf
ENERGY Television Label
Australian Greenhouse Office: Appliance Energy Program
http://www.energyrating.gov.au/considered.html?electronics
IEC 62087:2008: Methods of measurement for the power consumption of audio, video and related equipment
http://webstore.iec.ch/preview/info_iec62087-BD%7Bed2.0%7Den.pdf
IEC 62301:2005, Ed. 1.0: Household Electrical Appliances – Measurement of Standby Power http://www.iec.ch/
UK Market Transformation Program
http://efficient-products.defra.gov.uk/cms/market-transformation-programme/
California Energy Commission mandatory TV efficiency standards http://www.energy.ca.gov/2009publications/CEC-400-2009-023/CEC-400-2009-023-D-45-DAY.PDF
[1] ENERGY STAR defines this mode as the time when the product is connected to a mains power source, is not providing a principal function, and offers one or more of the following user oriented or protective functions which may persist for an indefinite time:
1) To facilitate the activation of other modes (including activation or deactivation of On mode) by remote switch (including remote control), internal sensor, timer.
2) Continuous function: information or status displays including clocks.
3) Continuous function: sensor-based functions.
[2] Ecos. Assessment of Options for Improving Energy Efficiency Test Procedures for Displays. 2010. http://www.efficientproducts.org/reports/tvs/Ecos_Display%20Test%20Procedure%20Report_FINAL.pdf
