A law that took effect last week requires new televisions for sale in retail showrooms to carry yellow Energy Guide labels, allowing consumers to evaluate and compare how much energy different models use and how much they cost to operate each year. My colleague Liz Judge blogged about the impact of these labels previously.

The most eye-opening information those labels contain is in the fine print.

“Your energy cost depends on your utility rates and use. The estimated cost is based on 11 cents per kWh and 5 hours of use per day. For more information, visit http://www.ftc.gov/energy.”

Try to wrap your head around that: According to our best estimates, new TVs are watched in one form or another for 5 hours each day. Consumers Union actually argued that 5 hours is an underestimate, and that manufacturers should estimate costs based on 8 hours of use.

The Energy Guide labeling program involves assumptions like this for most of the common household appliances that carry the yellow sticker. Sometimes, these numbers are a little opaque. Few of us know with much confidence whether we run our dishwashers 215 times a year like the label assumes, but we can all picture what watching 5 hours of TV each day looks like.

If you are set on purchasing a TV, an efficient model is always going to save energy compared to an inefficient similar model. That’s the point the Energy Guide labels make clear. But if you’re looking for real savings, the fine print shows an obvious way to save much more.

Writing in the New York Times in January, Mark Bittman—author of How to Cook Everything—ripped the Department of Agriculture for promoting “healthier” versions of processed junk food. “The truly healthy alternative to that chip,” Bittman wrote, “is not a fake chip; it’s a carrot. Likewise, the alternative to sausage is not vegan sausage; it’s less sausage.”

The same is true of televisions: The truly energy-efficient alternative to buying an inefficient TV is not buying an efficient TV. It’s buying a book, or a ball, or taking a walk outside. And the alternative to watching an inefficient TV for five hours a day is not watching an efficient TV for the same amount of time. It’s watching less.