Can I really live for free if I rent out the ADU or the other unit?
No. Rent from the other unit covers part of what the home costs each month, and you pay the rest. The number to look at is that remaining cost, next to the rent you pay now.
WHAT MOST PEOPLE ARE NEVER TOLD
FHA and Fannie Mae rules count 75 percent of the rent, and FHA's handbook ties the rest to vacancies and maintenance. A listing that says the rent covers the mortgage is usually using the full rent.
The comparison that matters is your cost to live there after rent, against the rent you pay now.
In worked examples Series has published, the rent covers about a third of the payment in one, half in another and two thirds on a fourplex. None covers all of it.
The claim of a free home comes from plain subtraction: full rent in, mortgage payment out. It skips the empty month between tenants and the repairs. And if the math counts every unit, it is counting rent from the one you will be living in.
FHA, which insures home loans, has a test of whether a three or four unit home pays for itself. The test counts rent from every unit, including yours. So a home can pass the test and still cost you money each month you live there.
GOOD TO KNOW
Plan on paying part of the cost yourself for as long as you live there, and on the whole payment in a month the other unit is empty. Every Series listing shows the cost with and without the rent, so check that both fit your budget.
Yours is a little different. They all are.
Tell us what you are looking at and what you are trying to do. We answer with the numbers on your situation.
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WHERE THIS COMES FROM
- HUD Handbook 4000.1 (FHA), Self-Sufficiency Rental Income, section II.A.1.b.iv(B)(3)(c) (page 171, revised 8/12/2026)
- HUD Handbook 4000.1 (FHA), Rental Income, section II.A.4.c.xii(I) (page 241, revised 8/12/2026)
- Fannie Mae Selling Guide B3-3.8-02, Rental Income from the Subject Property (09/02/2026)
- The House Hacking Bible, chapter 9, The False Security of Cash Flow (Series Homes)
Researched and written by Series Homes. Checked against its sources on . Lending rules change. This page is general information, not a loan offer or legal or tax advice.