There are other ways to do this, too, especially for those with family situations:
1) Rent to a foreign student under 18 who is getting a year of "American english / high school".
2) Foster parent
Obviously both the above come with a commitment to provide security and caring for the minors.. then there is :
3) English experience - Home Stay -- e.g., for adults taking english locally, you provide a week of accommodation and family interaction.
4) bnb / couch surfing
5) Boarders, other -- e.g provide meals and a room for university student
The key is an expensive housing market, a spare room, and a good location.