I have started one that is even better than the one hosting language students. I host AND teach the language students. This pays me $700 per week plus $100 for airport pick up. If they are under 18, I get an additional $100 for the week. It is a lot of work -- 15 hours of teaching each week, but the money is worth it. Hopefully, it will pick up as I get a student only every other month.
How did you get involved with that?
I found a company on the internet that works with an agency in Japan. I applied, a representative came to my home and now I teach the students. The company recruits retired teachers and actually is short on teachers.
Google 'living with a teacher' or 'language schools'.