Rental Property Investor · NH · Member since 2023 · 444 posts · 419 votes
That's the whole idea behind house hacking, and it's the reason I own real estate today.
In early 2022, my wife and I bought a 2-family in Manchester. We lived in one unit and rented the other for $2,000 a month, heat and hot water included.
So here's the math I'd run on any house hack:
Start with the full monthly payment (principal, interest, taxes, insurance)
Subtract the rent from the other unit
Add back any utilities you're covering for the tenant
What's left is your real cost of housing
For us, that was about $700 a month. In one of the nicest neighborhoods in the city.
Now, here's the part that actually built the portfolio. We kept living like our housing cost more. We banked roughly $2,000 a month, and after a year that was about $24K. That became the down payment on our next house hack, the one we live in now.
Full transparency: we bought at 3 to 4% rates. At today's rates, the same building produces a different number, so run it with a current quote before you get attached to mine.
But the principle holds at any rate. Your housing payment is usually your biggest monthly expense. Get it as close to zero as you can, and save the difference on purpose.
What's your real housing cost right now, after everything?
Andrew, I like the way you’re looking at house hacking as a way to reduce your biggest monthly expense and then deliberately save the difference for the next acquisition.
One thing I’d add is that I’d track the rental side separately from the personal side from day one. With a 2 family where you live in one unit, you have both personal and rental use, so the allocation of expenses, improvements, and depreciation matters. I’d also separate the cash flow calculation from the tax calculation. Your actual housing cost might be $700 a month, while the rental portion can have a very different taxable result once depreciation and other allowable expenses are factored in.
If someone is planning to repeat this strategy with multiple house hacks, getting that first property set up and documented correctly can make the next acquisitions much easier to analyze. The bigger lesson is exactly what you said: don't just let the savings disappear into your lifestyle. Turn that lower housing cost into the capital for the next deal.
Feel free to DM me, I’d be happy to send over a few resources that might be helpful.
good math. one line i'd add when the house hack is a single family rented by the room instead of a 2 family: the utilities.
with a duplex the other unit usually has its own meters. rent the bedrooms in one house and the power, water and wifi stay in your name for everybody. so in your "add back" line use the real bills for that many people, not what your family used to pay. it runs a lot higher.
second thing: price each room off what rooms near that house actually rent for. not the house rent divided by the bedrooms. mine run $600 to $775 a room and the bigger room with its own bath is always the top one.
do that and the "real cost of housing" number is honest before you buy.