Estimate effective housing cost, cash flow, and your savings vs renting
House hacking is the strategy of buying a small multifamily property (or single-family home with rentable space) as your primary residence, living in one unit, and renting out the others. The rental income offsets — and often fully covers — your mortgage payment. It's one of the few legitimate ways to get a foothold in real estate investing without the 20-25% down payment required for traditional investment properties.
The structural advantage is owner-occupied financing. The Federal Housing Administration (FHA) and conventional owner-occupied loan programs accept down payments as low as 3.5% (FHA) or 5% (conventional), compared to 20-25% for non-owner-occupied investment property loans. On a $350,000 fourplex, that's the difference between $12,250 down (FHA) and $87,500 down (investment loan). Combined with rental income from the other units, the math can produce an effective housing cost below what you'd pay in market rent — or in the strongest deals, eliminate housing cost entirely.
1. Small multifamily (duplex / triplex / fourplex). The textbook strategy: buy a 2-4 unit residential property, live in one unit, rent the rest. Four units is the upper limit for residential financing — five-plus moves the property into commercial loan territory, which dramatically changes the underwriting. A fourplex is the sweet spot because the three rental units typically produce enough income to cover the mortgage entirely.
2. Single-family with rented bedrooms. Buy a 3-5 bedroom single-family home, live in one bedroom, rent the others to roommates or via room-by-room leases. Lower barrier to entry than a multifamily (single-family homes are more available in most markets) but more operational complexity from sharing common spaces with tenants.
3. ADU (accessory dwelling unit) house hack. Buy a single-family home with an existing detached ADU, garage apartment, or basement apartment. Live in the main house, rent the secondary unit. Lower rental income than a true multifamily, but cleaner privacy separation and far easier to qualify for than a fourplex in expensive markets.
4. Short-term rental hybrid. Buy a property with a separate guest suite or basement unit and rent it short-term (Airbnb/VRBO) while living in the main space. STR income per night is typically 2-3× the equivalent long-term rent, but with materially higher operational work, vacancy, and regulatory exposure. Verify local STR rules before underwriting.
FHA loans are the most common house-hack financing because of the low down payment and accessible credit requirements. Key requirements for 2-4 unit FHA loans in 2026:
Conventional loans (Fannie Mae/Freddie Mac) also support owner-occupied multifamily with 5% down on a duplex and 15-25% on 3-4 unit properties. Conventional rates are typically 0.25-0.75% lower than FHA, and PMI (the conventional equivalent of MIP) drops automatically at 80% LTV instead of requiring a refinance. The trade-off: stricter credit (typically 680+ FICO) and tighter DTI requirements.
FHA and conventional owner-occupied loans require at least 12 months of owner-occupancy. After that, you can move out and convert the unit to a rental. Many house hackers stack these — buy a fourplex, live for a year, move into a new house hack, and convert the first property to fully-rented investment. After 3-4 properties stacked this way, the portfolio is meaningful.
Yes — 75% of projected rents from the units you won't occupy count toward your qualifying income on both FHA and conventional loans. The lender will require a rent schedule from the appraiser (a Fannie Mae Form 1007 for single-family or Form 216 for multifamily) documenting projected market rents.
FHA accepts credit scores as low as 580 (with 3.5% down) or 500-579 (with 10% down). Conventional owner-occupied loans typically require 680+ for the best rates. Below 620, FHA is usually the only realistic path.
For 3-4 unit properties with FHA financing, the property must "pay for itself": 75% of projected gross rents from all units (including the one you'll occupy) must equal or exceed the principal-and-interest payment. This test eliminates many fourplex options in expensive markets where prices have outpaced rents.
The cleanest setup is separately-metered units (each tenant pays their own electric, gas, water). If utilities are master-metered, options include: a flat monthly utility add-on to each rent (common), RUBS (Ratio Utility Billing System) that allocates costs by unit size or occupancy, or rolling utilities into rent and absorbing the variability. Verify how the property is currently set up before underwriting.
Yes. Married couples and unmarried co-borrowers both qualify for owner-occupied financing as long as at least one borrower occupies the property as their primary residence. Both incomes can be used to qualify, which often makes the deal easier.
Nothing — your existing loan stays in place at the owner-occupied rate as long as you genuinely occupied the property as required. The rate doesn't change because you move out after the one-year requirement is satisfied. This is a key reason house hacking is such an efficient strategy: you get owner-occupied financing terms on a property that ultimately becomes a pure investment.