House Hacking & Multi-Family: Reducing Living Expenses
Owner-occupant mortgages are the cheapest borrowing most people will ever get, and they extend to buildings with up to four units. That single quirk is the whole idea: live in one, rent the others, and buy an investment property on terms an investor can't get.
The four-unit line
Residential mortgages cover buildings of one to four units. At five, the property becomes commercial, and commercial lending means larger down payments, shorter terms and rates that reflect a business loan rather than a home loan.
So a fourplex you live in is financed as a house. You get owner-occupant rates and down payment options, on a building that is three-quarters investment property. That's the entire mechanic, and it is the cheapest access to leveraged real estate available to an ordinary person.
The trade-off is that you have to live there, usually for at least a year under the loan terms. You'll share walls with your tenants, and being the landlord of the person on the other side of the wall is a different experience from owning something across town. The financing advantage is real; so is the part where someone knocks on your door about a leak on a Sunday.
1–4 units is residential financing. 5+ is commercial, on much worse terms.
What the headline number leaves out
The appealing version goes: PITI is $3,000, the tenant pays $1,750, so you live for $1,250. Every part of that is true and it is not the whole calculation.
The $1,750 is gross rent. Out of it come vacancy between tenants, repairs on a building with more of everything to break, and a reserve for the roof and systems you now own outright. Counting on the full rent every month is the single most common error in these projections, and a two-month vacancy erases most of a year's advantage.
There's a tax dimension too. The rented portion of the building can be depreciated and its expenses deducted, apportioned by the share you don't occupy — genuine benefits that the headline version also skips. The honest summary is that house hacking usually works, at a smaller margin and with more work than the pitch suggests.
Owner-occupant financing covers 1–4 unit properties at far better rates and down payments than investment loans. Rent from the other units offsets your housing cost — but the offset is smaller than the headline once vacancy, repairs and reserves are counted.
Sources
- Buying a house: Tools and resources for homebuyers — Consumer Financial Protection Bureau (2026)