House hacking: live with tenants, pay less mortgage, question your life choices occasionally

By Tom, CPA · Updated October 25, 2026

TL;DR: House hacking means living in part of a property and renting out the rest: a unit in a duplex to fourplex, an accessory dwelling unit (ADU), or spare bedrooms. Rent offsets your housing cost, often dramatically. Owner-occupied loans like FHA allow down payments as low as 3.5% on 1–4 unit properties. The rented portion is a rental for tax purposes: you split expenses, depreciate that part, and it affects your home-sale exclusion later.

Educational only, not tax, legal, or investment advice. Examples are illustrations, not predictions. Rules and limits change; verify current figures and talk to a qualified professional about your situation.

Housing is the biggest line in most budgets, which makes it the biggest lever for FIRE. House hacking pulls that lever hard: instead of paying your mortgage, you get tenants to pay most or all of it. The trade-off is that the tenants live right there. Through a shared wall. With a drum kit, potentially.

Lavish Larry wants a single-family home with a three-car garage and a home theater. Frugal Fran bought a duplex, lives in one side, and her tenant pays most of the mortgage. Larry's house is nicer. Fran's savings rate is higher. Background: rentals for FIRE.

CPA Warning Label: Loan programs have occupancy, credit and reserve requirements, and local zoning, licensing and landlord-tenant laws vary. Splitting a home between personal and rental use creates real tax complexity. Get qualified advice before buying.

Models

The best model depends on your local market, your tolerance for proximity, and what's legal where you live. Check zoning, rental licensing and HOA rules before you buy, not after. Some cities restrict ADUs, room rentals or short-term rentals, and some HOAs prohibit rentals entirely.

Financing rules

House hacking's superpower is owner-occupied financing. Loans for homes you'll live in generally have lower down payments and rates than investment property loans.

• FHA loans: HUD says FHA down payments can be as low as 3.5% of the purchase price, available on 1–4 unit properties. FHA insurance has credit score, occupancy and mortgage insurance requirements. Borrowers typically must intend to live in the property as a principal residence. 3–4 unit properties face additional underwriting tests.
• Conventional loans: owner-occupied conventional loans can have low down payments for single-family homes, with higher requirements for multi-unit properties. Terms vary by lender and loan program.
• VA loans: eligible veterans and service members may be able to buy owner-occupied 1–4 unit properties with no down payment, subject to VA rules.
• Rental income for qualifying: lenders may count part of the projected rent from other units toward your income, under program-specific rules.

Two cautions. First, occupancy requirements are real. Claiming you'll live in a property you won't is mortgage fraud, not a hack. Second, a low down payment means high leverage and mortgage insurance. A vacancy or a big repair hits harder when you have little equity.

Tax treatment of rented portion

IRS Publication 527 says that if you rent part of your property, you must divide certain expenses between the rental part and the personal part, as though you had two separate properties.

• Split expenses: mortgage interest, property taxes, insurance and utilities that serve the whole property are allocated, usually by square footage or number of rooms. The rental share goes on Schedule E.
• Expenses only for the rental unit (painting the tenant's unit, for example) are fully rental expenses. Expenses only for your unit are personal.
• Depreciation: you depreciate the rental portion of the building (not land), generally over 27.5 years. See real estate depreciation.
• Passive loss rules apply to the rental portion. See passive activity loss rules.

When you sell: the home-sale exclusion (Section 121) can shelter up to $250,000 of gain ($500,000 joint) on your residence if you meet the ownership and use tests. But IRS Publication 523 says that if part of the property was a separate rental portion and you didn't live in that part for 2 of the last 5 years, you must allocate gain between the residential and rental portions. Gain from depreciation taken after May 6, 1997, generally can't be excluded. Units in a duplex are typically separate. See the Section 121 guide.

The rental portion can also be exchanged under Section 1031 in some circumstances, which can combine with the 121 exclusion on the personal portion. That's advanced territory. See 1031 exchange basics.

Landlord realities

The spreadsheet version of house hacking is beautiful. The lived version includes:

• Proximity. Your tenant knows when you're home. You'll hear about the leaky faucet at dinner.
• Fair housing law. Tenant screening must comply with federal, state and local fair housing rules. Some owner-occupied small properties have limited exemptions under federal law, but state and local rules may be stricter and advertising rules still apply.
• Landlord-tenant law. Security deposits, notice periods, habitability and eviction rules vary widely by state and city.
• Vacancy and turnover. Budget for empty months, cleaning, repairs and advertising.
• Repairs and capex. Two units means two kitchens, two water heaters and more things to break.
• Insurance. You'll likely need a policy that covers rental use, plus liability coverage.
• Boundaries. Written leases, clear rules and a consistent process protect the relationship and you.

The best house hackers treat it as a small business from day one: separate bank account, written leases, documented maintenance, receipts for everything. Your future tax return will thank you.

Example

Illustration: Fran buys a $480,000 duplex with an FHA loan and 3.5% down ($16,800). At an assumed 7% rate, principal and interest on the $463,200 loan is about $3,080 a month. Add FHA mortgage insurance, property taxes and insurance, and assume a total of about $3,900 (rates and costs vary). She rents the other unit for $2,100 a month.

• Fran's net housing cost: about $3,900 - $2,100 = $1,800 a month, before maintenance and vacancy. Budget another $300 or so for those, for an effective cost around $2,100.
• A comparable one-bedroom rental nearby might cost her $1,800. So she's paying a few hundred dollars more than renting, while building equity on a $480,000 property and owning a unit she can rent out later.
• Taxes: half of the shared costs (interest, taxes, insurance) go on Schedule E against $25,200 of rent, along with depreciation on half the building's value. The other half of the mortgage interest and property taxes may be deductible as personal itemized deductions if she itemizes.
• In five years, she moves out and keeps both units as rentals. At that point, the whole property is a rental, and her future home-sale exclusion on her old unit depends on the 2-out-of-5-year timing.

Larry buys the $480,000 single-family home with a home theater. His payment is similar, and he has no tenant. Over the same five years, Fran's tenant has paid roughly $126,000 in rent, before vacancy, toward her costs.

Run your own numbers with the rental property cash flow calculator. Compare with REITs vs rental property and plain index fund investing.