Compact, “micro” apartments are an up-and-coming trend in Chicago’s urban living scene, data from StorageCafe shows.

Chicago is the midwestern city with the second-highest percentage of micro-housing units in its rental inventory. Seven percent of all apartments are smaller than 400 square feet, which is approximately half the size of a typical unit. Some Chicago units are as small as 110 square feet.

In many cities, apartments that small aren’t only rare — they’re illegal to build.

The tradeoff for less square footage, though, is a monthly rent nearly half the cost of a conventional Chicago apartment. The average rent for a typical apartment in the city is about $2,420 per month. But the average rent for a micro-unit is $1,263.

“Micro-housing is one of the most efficient tools we have to create more housing quickly and affordably, especially in urban areas where land is scarce and demand is high,” said David Nieman, partner at Neiman Taber Architects, adding that “micro-units play a critical role in expanding the supply of low-cost, market-rate housing.”

Ultimately, for many renters, like new grads, people who travel frequently for work, recent divorcees or young couples, living small just makes more sense.

“Affordability is clearly a big part of the story,” said Brad Hargreaves, founder and editor-in-chief of Thesis Driven. “There is a segment of renters who simply don’t need as much space and are willing to trade that space for lower rent.”