There are more than five million “zero-TV” households in the United States, according to Nielsen—but that doesn’t mean those homes aren’t watching video.

Zero-TV households are up from just more than two million in 2007, and now make up slightly less than 5 percent of U.S. households, according to Nielsen's Fourth-Quarter 2012 Cross-Platform Report. These are homes that could be defined as going beyond cord-cutting: they simply don’t consume live or on-demand video via a TV set at all.

That doesn’t mean they’re not using TV sets for other things: 75 percent of these homes still have at least one TV set, which they use to watch DVDs, play games or surf the Internet.

For watching live or on-demand video, these households are using other devices. About 37 percent watch TV and movies on a computer, while 8 percent do so on smartphones and 6 percent watch on tablets.

"Most people watch TV in their living rooms using traditional cable or satellite options," Nielsen said. "In fact, more than 95 percent of Americans get their information and entertainment that way. But as we explored what the other 5 percent are doing, we found some interesting consumer behaviors that we want to keep an eye on."

Only 18 percent of the zero-TV group said they'd consider subscribing to TV services, Nielsen found.

The average American spends more than 41 hours each week — nearly five-and-a-half hours daily — engaging with content across all screens. They spend most of that time (more than 34 hours) in front of a TV, and consumers spend three of those TV hours watching time-shifted content.

Viewing behavior varies by ethnicity, though: the average African-American spends close to 55 hours, Hispanics just over 35 hours and Asian Americans spend more than 27 hours.

When it comes to demographics for zero-TV households, Nielsen also found that the zero-TV homes tend to be younger, with almost half under the age of 35. The majority are non-Hispanic (85.5 percent), while 10.1 percent are Asian, 9.5 percent are Black and 8.4 percent are Hispanic.

Also, zero-TV homes tend to be populated by viewers who live alone and have no children (80.9 percent, vs. 66.7 percent for traditional TV).