See IRS Publication 527 Residential Rental Property page 19 - https://www.irs.gov/pub/irs-pdf/p527.pdf#page=19

Used as a home but rented less than 15 days.

If you use a dwelling unit as a home and you rent it less than 15 days during the year, its primary function is not considered to be rental and it should not be reported on Schedule E (Form 1040). You are not required to report the rental income and rental expenses from this activity. The expenses, including qualified mortgage interest, property taxes, and any qualified casualty loss will be reported as normally allowed on Schedule A (Form 1040).