Imagine if we built cars the same way we build houses. First, a typical buyer would meet with the car designer, and tell them what kind of car they want. Then the designer would draw up plans for the car.The buyer would call different car builders in their town and show them the blueprints. And the builders might say, "Yeah, I can build you that car based on this blueprint. It will cost $1 million and it will be ready in a year and a half."There are lots of reasons why homes are so expensive in the U.S., zoning and land prices among them. But also, the way we build houses is very slow and very inefficient. So, why don't we build homes the way we build so many other things, by mass producing them in a factory?In this episode, the century-old dream of the factory-built house, and the possibility of a prefab future.This episode was produced by Emma Peaslee. Molly Messick edited the show, and it was fact-checked by Sierra Juarez. Brian Jarboe mastered the episode. Jess Jiang is our acting Executive Producer.Help support Planet Money and get bonus episodes by subscribing to Planet Money+ in Apple Podcasts or at plus.npr.org/planetmoney.