Explanation of Correction Factor for Automatic Brightness Control
PurposeIn the interest of transparency and enabling stakeholder and EPA discussion around EPA's proposed
approach to developing and implementing this correction factor, EPA is sharing this summary
explanation.
Background
EPA is committed to adopting the television test procedure currently under development by the U.S.
Department of Energy (DOE). Therefore, in the Draft 2 Version 6.0 Televisions Specification, EPA isproposing the same Automatic Brightness Control (ABC) testing requirements as in the Department ofEnergy’s Test Procedure Notice Of Proposed Rulemaking (NOPR). EPA understands that the new ABC
test method will affect the reported On Mode power for Televisions shipped with ABC enabled. In order topreserve the utility of its large dataset and avoid retesting products, EPA has conducted additional
research, testing and analysis to provide more information on how this new test method would affect thecurrent Televisions data. EPA then derived a correction factor, which was used to estimate how
televisions tested under the old ABC test method would perform under the new method.
Testing
EPA conducted testing on seven different television models representing the major television types, major
manufacturers and screen technologies. These seven televisions were tested according to the current
ABC test method and the proposed ABC test method. This information was combined to develop an“average ABC response curve” representing the average change in power use as room illuminancechanges. This average curve can be seen in the figure in black; while the percentage power at eachtested illuminance point is shown in the table, below:% of Maximum Brightness Power[%]% of Max Brightness Power120%

Percentage of Power at 300 lux

100%

Sample 1

80%

Sample 260%

Sample 3

40%

Sample 420%

Sample 50%
110100

Room Illuminance [lux - logarithmic scale]

Sample 6
Sample 7

Room Illuminance (lux)Percentage of Power at 300 lux
01050
100

57.03%
74.64%
93.15%
98.66%

300

100.00%

EPA understands that this average ABC response curve does not perfectly represent the implementationof ABC for all televisions; however, it does provide an appropriate proxy for assessing how the new ABC
test procedure might affect the data in EPA’s dataset.
DataThe average ABC response curve was applied to all ENERGY STAR qualified televisions that weresubmitted with ABC enabled (556 models out of the total 1697). The power at each room illuminance (10,50 and 100 lux) was calculated by multiplying the power at 300 lux as measured for each model by thepercent of power at 300 lux for each room illuminance as calculated from the average ABC responsecurve. Of the data that was adjusted, this increased the reported On Mode Power by an average of12.9 W with a minimum of -15.4 W and a maximum of 62.1 W. No change was made to models tested
and submitted with ABC off.
With this adjustment in place, the dataset was treated as if all televisions had been tested according tothe test method as proposed in the Draft 2 Version 6.0 Televisions specification. This method of dataadjustment was favored by EPA over an adjustment to the calculation of On Mode Power as proposed in
Draft 1. EPA agrees with the stakeholder comments that altering the calculation of On Mode Power in thespecification provides data that is incongruous with real world operating conditions and furthermore thatthe implementation of ABC is generally more complex than a linear relationship between screen
brightness and room illuminance.