There’s a big difference between affordable housing and housing that is affordable.

Affordable housing is the government-subsidized kind. The latter, on the other hand, describes the “ways that architects or engineers have reduced the cost of owning a house, renting a house, or constructing a house,” says Marc Norman, who recently curated an exhibit on the subject at The Center for Architecture in New York City. It’s distinct from affordable housing, which he says “is not always cheap to build.”

With Designing Affordability: Quicker, Smarter, More Efficient Housing Now, Norman contends that this niche area of interest isn’t so niche anymore. Rather, he says, it now seems to be something “lay people are talking about all over the country.” In big cities, especially, those discussions are happening out of necessity. There are fewer and fewer square feet to lay claim to, and what can be claimed still costs a lot. Census data from this summer shows that even rent-stabilized tenants in NYC are paying more than 30 percent of their incomes on rent—enough to qualify as “rent burdened.” The same is true for many city dwellers with market rate rents.

Hence the exhibit. Norman breaks the show down into seven methods designers can use to create housing that is affordable, and draws on 23 examples from around the country to illustrate how these methods are implemented in the real world.

Leverage Land

Land can be one of the biggest drivers of cost when building a house, Norman says. Many projects in this camp circumvent this issue by using land that wasn’t used for housing previously. Take the Alley Flat Initiative in Austin, Texas, which has one of the most overvalued housing markets in the country. The initiative makes use of Austin’s many alleyways by filling them with two-story residential apartments.

Deploy Technology

MIT’s Media Lab harnessed the power of sensors and Internet of Things-branded products to make a 200-square-foot prototype apartment perform like one four times that size. The system allowed inhabitants to use hand gestures or voice commands to flip, move, and stow the house's transformable furniture (think Murphy beds and foldable dining room tables). “We can actually be incredibly efficient, but have all the comforts in a smaller space,” Norman says.

Build Modularly

Architects have championed the idea of the modular home for decades, but we’re only now starting to see them appear at scale. The 250- to 370-square-foot MY Micro NY apartments going up in NYC are assembled from modules that are built off-site and later hoisted into place with a crane.

Reimagine Public Housing

Many government-led housing projects that went up during the 1950s, 1960s, and 1970s still stand today, but include swaths of parking spaces that city-dwellers don’t use. “It’s just leftover space,” Norman says. Two projects—"9 x 18" in New York City and Vandamme Nord in Paris—would convert that unused space into retail outfits, or shared urban parks. Those amenities improve on nearby public housing without requiring any work on the apartments, themselves.

Build Incrementally

A housing model in which you build incrementally, Norman says, calls for setting up a basic house with a roof that can easily accept additions, whenever the inhabitants can afford them. This favela-like approach is gaining legitimacy and traction in Rocinha, one of Rio de Janeiro’s biggest slums, as well as in Brooklyn and San Francisco. The Urban Works Society in San Francisco, for instance, looks at how Marina-style and Victorian homes in the area could be added to architecturally, allowing families to expand without purchasing new property in a city with sky-high rent.

Rethink Home

Life at home no longer means one family in one dwelling. Urban areas impose de facto communes on us; more and more we work from home. Projects like Lo-tek, a coworking hotel in New York City, respond to those vanishing boundaries by offering up spaces that can double or triple in functionality.

Build Simply

Building simply calls for exactly that: using time-tested methods to build houses on the cheap. Norman points to the XS Houses in Houston, Texas, that follow the early 20th century shotgun housing typology most often seen in New Orleans. (It’s experiencing a comeback there, too.) The housing style originates in the Caribbean, and has a layout that connects the front door to the back, so it can self-ventilate, and a porch, so its owners have additional outdoor square footage.