House Hacking: How to Analyze the Deal
The trick is analyzing it twice — once as the place you live, and once as the rental it becomes when you leave.
$246 vs $604
Saved per month while you live there; lost per month once you move out.
Why one analysis is not enough
House hacking — buying a two- to four-unit property, living in one unit and renting the rest — is genuinely the cheapest legitimate entry into rental property. Owner-occupied financing means 3.5% down with FHA instead of 25%, on a building that produces income.
The trap is that the housing-cost view flatters everything. Of course your outlay is lower than renting: you have a tenant paying part of the mortgage and you put almost nothing down. That comparison tells you the house hack beats renting. It does not tell you whether you bought a good building — and one day you will move out, at which point the building is all you own.
View one: what it does to your housing cost
A $380,000 duplex, FHA at 3.5% down, 6.5% for 30 years
- Down payment
- $13,300
- Loan including upfront MIP
- $373,117
- Principal and interest
- $2,358/mo
- Monthly mortgage insurance
- $171/mo
- Property taxes
- $475/mo
- Insurance
- $150/mo
- Total housing outlay
- $3,154/mo
- Less rent from the other unit
- −$1,700/mo
Net housing cost: $1,454/mo — against $1,700 to rent something comparable.
On this view it is a clear win: you are housed for $246 a month less than renting, and roughly $340 a month of your payment is principal you keep. For $13,300 down, that is a very good outcome, and it is the honest case for house hacking.
View two: the building, standing alone
Now assume you moved out and rented your unit too. Both units at $1,700 — $40,800 gross — underwritten the same way as any other rental.
The same duplex as a pure rental
- Gross scheduled rent
- $40,800
- Less vacancy @ 5%
- −$2,040
- Effective gross income
- $38,760
- Taxes, insurance, management, maintenance, CapEx
- −$15,660
- NOI
- $23,100
- Annual debt service (including MIP)
- −$30,348
Cash flow: −$7,248/yr. DSCR: 0.76.
Both of these are true at the same time
What the second view is telling you
Not necessarily “do not buy”. It is telling you what has to happen between now and the day you move out:
| Path | What it requires | Effect on the example |
|---|---|---|
| Refinance out of mortgage insurance | Reaching roughly 20–22% equity, which with FHA generally requires a refinance rather than automatic cancellation. | Removes $171/mo — about $2,050 a year. Helps; does not close a $7,248 gap. |
| Rent growth | Time, and a market where rents actually grow. | Each 5% rent increase adds roughly $1,500 of NOI once variable expenses rise with it. Closing a $7,248 gap takes several of them. |
| Pay down principal or recast | Capital you may not have. | Directly reduces debt service, which is the binding constraint. |
| Buy better in the first place | A lower price, or a building with a higher rent-to-price ratio. | The only lever available before you sign. |
| Sell when you leave | Enough appreciation to cover 6–8% selling costs. | Legitimate — but then it was a housing decision, not an investment. Plan it as one. |
How to underwrite a house hack properly
| Do | Don’t |
|---|---|
| Model your own unit at market rent in the standalone view | Treat your unit as producing zero income forever |
| Include mortgage insurance in debt service | Assume it disappears on a schedule you have not verified |
| Budget vacancy and CapEx on the whole building | Assume self-management and self-repair are permanent |
| Compare net housing cost against real local rents | Compare it against your current below-market rent |
| Check the occupancy requirement and its term | Plan to move out early — the requirement is a legal obligation |
| Model the day you leave, explicitly | Decide you will “figure it out then” |
The number that makes a house hack work long-term
What house hacking is genuinely good at
Three things, none of which are cash flow: it gets you an owner-occupied interest rate and down payment on an income property; it teaches you landlording with the lowest possible stakes, because you are on site; and it converts your largest monthly expense into a partially productive asset. Those are real advantages and they justify a lot of thin numbers.
Just do not confuse them with having bought a good rental. Run both views in the free calculator — the standalone one is the same analysis as any other small multi-family purchase — and buy when both of them work.
Frequently asked questions
How do you analyze a house hack?
Twice. First as a housing decision: total monthly outlay minus the rent you collect, compared against what it would cost you to rent comparable space. Second as a standalone rental: all units at market rent, full operating expenses, and the actual debt service including mortgage insurance. Buy when both views are acceptable.
Is house hacking still worth it?
As a way to reduce housing costs and enter property ownership with a small down payment, it remains one of the strongest options available. As a way to acquire a rental that will cash flow after you move out, it is much harder at current rates, because the low down payment that makes entry cheap also leaves the building carrying more debt than its rents support.
Should I count my own unit as income in a house hack analysis?
In the standalone view, yes — at market rent, as if you had moved out. In the housing-cost view, no; instead compare your net outlay to what renting elsewhere would cost you. Mixing the two conventions is the most common source of confusion in house-hack numbers.
How long do I have to live in a house hack?
Owner-occupied loan programs typically require you to occupy the property as your primary residence for at least twelve months. This is a contractual and legal obligation rather than a guideline, so plan the timeline before you buy.