this is an excerpt from airbnb: Here is the link: https://assets.airbnb.com/eyguidance/us.pdf
How to report rental income and expenses
Rental income and expenses are reported on Schedule C or Schedule E of your tax return (Form 1040).
If you are a real estate dealer who is engaged in the business of selling real estate to customers with
the purposes of making a profit or an owner of a hotel, motel, etc., who provides services (maid
services, etc.) for guests, report the rental income and expenses on Schedule C. If you are not, report
the rental income and expenses on Schedule E. Schedule C income may be subject to self-employment
tax, while Schedule E income may be subject to Net Investment Income Tax.
Most individual taxpayers report residential rental income and expenses on Schedule E
I'm glad I don't have that question. My experiences with Airbnb rentals, as a customer, has been 100% use of the entire house, or at least guest house. How I read this question, is that the "tenant" may get exclusive use of a bedroom, which at other times may be used as an unpaid, actual guest bedroom; and shared use of a kitchen and living area. There's probably a bathroom or two involved, also. If 30% of the house is rented 25% of the time for exclusive use, and 70% of the house is rented 25% of the time for shared use, how is depreciation calculated? If the bedroom and bathroom are used only for rental, does it make a difference that the rentals are mostly just weekends between May and September?
Don't know if IRS would agree with me, but if I were doing taxes for your hypothetical client to make it simple for depreciation I would say square foot of home X 1/2 X (days rented) / (days lived in).
as an example: home 2400 sq ft, rented 40 days, lived in home 320 days.
2400 / 2 = 1200 40 / 320 = .125
1200 X .125 = 150 sq ft for rental space
Not perfect, but close enough for me. 🙂