I really liked hosting my finished basement on AirBnB, but I consider it a well-paying side-gig rather than a passive income. You can make your AirBnB pretty automated by hiring cleaning and hosting services, but I couldn't justify paying someone $50 to come clean when I could do it myself in an hour. I have the benefit of a great location in Seattle, in a residential neighborhood about two miles from downtown with street parking, public transit, great parks and restaurants, so I had an easier time finding guests than a friend who hosted a few miles further out from the city center. Competition is fierce, and the local market is flooded with $50 listings, so I had to make sure I had a really great listing, with clear copy and gorgeous photographs. My home is also quirky, with pet chickens and thrifted furniture, so it has more personality than the nicer but impersonal listings run by full-time AirBnB hosts. My basement doesn't have a kitchen, but I got an energy efficient mini-fridge, a microwave, and an electric kettle, which was sufficient for most guests. I started out charging $50 a night, plus $10 extra for more than 2 guests, and a $10 cleaning fee. Once I was established with glowing reviews, I could charge at least $100 night, $15 extra for more than 2 guests, and a $20 cleaning fee. I was at about 50% occupancy in winter and probably 80% occupancy in summer.
When I took a break from hosting, after 9 months, I had about 50 reviews displaying as a 5-star average.
All in all, I figured I was netting about $100 an hour for my work hosting on AirBnB, but I never did the math in terms of taxes and increased utilities from wasteful guests. Here in the states, it is pretty complicated declaring your AirBnB income on your taxes, but you can also write off some of your utilities, supplies, and home improvements as business expenses.
I did AirBnb for about 9 months in 2015-16, and took a break when I had a baby in 2016, and I hope to start up again this summer. (Have a responsible tenant in the space now, who pays a fraction of what I could make on AirBnB, but there's also no extra work involved.)