In order to project the potential energy savings from implementing energy efficiency policy, realistic usage profiles are essential. In the case of televisions (TVs), these usage profiles can be complex due to the range of functions TVs provide, the increasing number of TVs per household, the increasing hours of TV viewing, and the changing usage of a TV over its lifetime. Calculating the energy use of a TV over its lifetime is a challenge because, when a new TV is purchased, the old TV is often maintained and used less frequently in another room in the home, rather than being disposed of. Due to limited access to comprehensive usage data, previous analyses have either assumed a single static usage value, based on either metered or survey data, or estimated a usage profile adjusted from measured values to account for possible increases in future viewing. In this analysis, we investigate detailed TV usage over time using historical metered TV use data from more than 12,000 U.S. households, collected by The Nielsen Company. We found that the main TV in a household is used for 7.2 h per day, while other TVs are used for 2.5 h per day or less. We also found that 65 % of TVs in the total stock are considered the "main" TV. Combining this information, we determined the mean hours per day per TV to be 5.5.