And one more piece of supporting documentation:
"If you do choose to rent the property to a friend or relative below market value, just be sure to reflect this in your tax return. You will still be able to claim property taxes on the property, a well as your mortgage interest if the rental is your secondary property."
There is no mention of claiming mortgage payments or any other expense "up to the amount of the income." Source: https://laporte.com/knowledgecenter/tax-services/tax-consequences-of-charging-below-market-rent
