House hacking: how it works, the real numbers, and who it suits

House hacking is the plainest idea in real estate dressed up in a catchy name: buy a place to live, rent out the part you do not need, and let the rent pay down the building you own. Most people picture a two-to-four-unit property where you live in one unit and rent the rest, but it also covers renting spare bedrooms, a finished basement, or a separate accessory dwelling unit in the back. The mechanics are the same either way. You occupy, you rent, and your tenants carry some or all of your housing cost.

What makes it worth a whole page is not the concept, it is the two things the motivational versions skip. The first is the financing edge: because you live there, a small multifamily can be bought with owner-occupied terms instead of investor terms, which changes the down payment and the rate. The second is the tax split nobody explains: the day you rent out half your home, half your home becomes a rental property to the IRS, with its own income, its own deductions, and its own depreciation schedule. Both deserve real numbers, so this page works a duplex from purchase to Schedule E.

How house hacking actually works

The defining feature is owner-occupancy. You are buying a primary residence that happens to produce rent, not an investment property that happens to have your name on the door. That distinction is the whole engine. It opens the door to financing meant for homeowners, which on a 2-to-4-unit property is dramatically cheaper to enter than the 20% to 25% down a pure rental usually requires. The owner-occupied loan programs and what they require are a topic on their own, covered in house hacking financing.

The trade you make for that cheap entry is that you have to live there. Owner-occupied programs generally expect you to move in within roughly 60 days of closing and to occupy the property for at least a year. That is an intent requirement, not a prison sentence, but it is real, and stretching the truth about it on a loan application is mortgage fraud. After your occupancy period you can move out and keep the property as a full rental, which is exactly how a lot of small portfolios begin: one house hack, then another, each one started on owner-occupied terms.

A worked duplex, start to finish

Say you buy a duplex for $340,000 and put 5% down, so $17,000, with closing costs of roughly $10,000 you bring to the table. Your loan is $323,000. At a representative owner-occupied rate, principal and interest run about $2,050 a month; add property taxes and insurance and call the full housing payment $2,650. You live in one unit. You rent the other for $1,500 a month.

• Your out-of-pocket housing cost. The $1,500 of rent offsets your $2,650 payment, leaving you paying about $1,150 a month to live in half a duplex. If comparable one-bedroom rent in your area is $1,400, you are housed for less than renting, and you own the building.
• The income side is real rental income. That $1,500 a month, $18,000 a year, is taxable rent. It is not a discount on your mortgage; it is income you report, against which you deduct the rental share of expenses.
• Day-one yield is modest, and that is normal. A house hack rarely cash flows like an arm's-length rental, because you are also consuming half the property yourself. The return shows up in cheap housing now and a financed asset later, not in a fat monthly check.

Before you sign anything, treat the rented unit the way you would any deal: pull real rent comps instead of trusting the listing, and run the rental half through how to analyze a rental property so you know the unit pencils on its own. A house hack that only works because you live there for free is a house hack that traps you in place.

The tax split everyone skips

Here is the part that turns a homeowner into a landlord. The IRS treats a property you both live in and rent as a dwelling unit with personal use, and it makes you divide it. The space you occupy is personal: no rental deductions, same as any homeowner. The space you rent is a rental: its share of income and expenses lands on Schedule E. The governing rules are in IRS Publication 527, which covers expense allocation for a dwelling unit you also use personally.

You allocate shared costs by a reasonable measure, usually square footage or unit count. In an even duplex where each side is the same size, that is a clean 50%. Of the mortgage interest, property taxes, insurance, and utilities you pay across the whole building, half is a rental deduction and half is personal. Repairs that touch only the rented unit are fully deductible; repairs to your own unit are not; repairs to the shared roof or furnace get split by the same fraction.

Then there is depreciation, which is where house hackers leave money on the table. You depreciate only the rental share of the building, not the land and not your own half. On a $340,000 duplex, say the land is worth $60,000, leaving $280,000 of building. The rental half is $140,000 of depreciable basis. Residential rental property depreciates straight-line over 27.5 years using the mid-month convention, so a full year is roughly $5,090, the first partial year less depending on when the unit went into service. That deduction is computed on Form 4562 and carried to Schedule E. The deeper mechanics, including how the first-year factor works, live in rental property depreciation.

Who house hacking actually suits

The fit is narrower than the enthusiasm suggests. House hacking suits someone who can tolerate living next to or among tenants, has the cash for the down payment and closing costs plus a real cash reserve for the inevitable repair, and wants to compress the cost of housing while learning to be a landlord on training wheels. The proximity is the feature for some and the dealbreaker for others. When your tenant shares a wall, a clogged drain at 11pm is your problem in a way it is not when you self-manage from another state.

It suits the first-timer especially well, because it is one of the few ways to buy a small multifamily without investor-sized cash, and it pairs naturally with the broader path in how to buy your first rental property. It suits the patient less obviously: the real payoff is years out, when you move on and the whole building becomes a rental that funds the next one. That is how a house hack becomes the first brick in a rental property portfolio rather than a one-off.

It does not suit someone who needs day-one cash flow, someone who cannot live with tenants nearby, or someone counting on the strategy to make a bad deal good. The financing is cheaper, but the property still has to be a property worth owning. Run the rental side on its own merits, and if it only works because you are subsidizing it with your own occupancy, keep looking.

From two units to one Schedule E

The moment you rent that other unit, you have two jobs that used to be one. You are a homeowner tracking the cost of your home, and you are a landlord tracking rent received, the rental share of every shared bill, and a depreciation schedule on half a building. Most homeowner tools handle the first job and ignore the second, which is how house hackers reach tax time with a year of mingled receipts and no clean rental number. I built my own tool because spreadsheets kept dropping things like exactly this split, where one bill has to land partly on Schedule E and partly nowhere.

rents.ai tracks the rented unit as its own line: the income you record, the expenses you tag to it, and straight-line MACRS depreciation on the rental share, rolled into the Schedule E figures a regular homeowner toolkit cannot produce. The limitation worth saying plainly is that it will not do the allocation for you. You decide the personal-versus- rental fraction and enter the rental portion; the app does not know which half of the furnace bill is yours. You can sketch the day-one numbers in the cash-on-cash calculator before you buy, then track the real ones once you own it. A house hack is two stories in one building. The sooner you keep them on separate pages, the easier the year ends.