Tiny houses are showing up more and more in the media. A documentary released in 2013, Tiny, helped fuel the fire, and a 2014 Internet-based TV series, Tiny Home Nation, is stoking the flames.

But for those who haven’t been following the tiny house talk, what is a “tiny house”, exactly?

According to the Small House Society, an organization that collects and disseminates information about the ‘small house movement’, there is no set size that defines them—though they say that houses under 500 square feet are most often associated with the movement.

For a little perspective, U.S. houses built in 2014 averaged 2,600 square feet, bigger than the previous record of 2,400 during the real estate bubble years (and much bigger than 1,725 in 1983).1

Tiny homes have their critics. Since many of them are plopped down on a decent-sized plot of land and lived in by one or two people, they’ve been called out for not really improving “density”—that is, fitting more people into space-efficient communities without going totally inhumane and claustrophobic.

Tiny houses have also been made fun of on HBO’s Portlandia.

On the other hand, there are a lot of big fans of tiny homes, and more and more companies out there who are willing to design and build them.

Do they have enough of a market-base to support this tiny craze?

There are a couple of demographics that might make this little market keep growing. One is the aging Baby Boomer population. They are ready to downsize to smaller dwellings and save on upkeep and energy costs.

The other segment is the up-and-coming Millennials. While they might not always be content to live in smaller spaces than they grew up in, it may take them a while to find their footing career-wise as our economy slowly gets off the ground.

So if you’re not ready for a big mortgage, and you’re going to put off having kids until your career has had a chance to take off, a small house might just—literally—fit the bill.

Aside from living in a tiny house (on wheels or not) somewhere on a tract of land outside the city, another living trend helping some people find more affordable prices in big cities are the very modestly sized dwellings called micro-apartments.

1. http://money.cnn.com/2014/06/04/real_estate/american-home-size/