How to finance a rental property: a guide for 1-10 unit landlords

Financing the next rental is one decision tree, not a pile of loose questions, and almost nobody walks you through the whole thing because almost everybody writing about it is selling the loan. The pages that rank are lender product pages and shallow lists, each pushing the one product the publisher happens to offer. What you actually need is to see how the choices connect: whether you live in it or not, which loan type fits, where the down payment comes from, and what each path does to your taxes and your records afterward.

So this runs one example all the way through. Say you are buying a duplex for $250,000, you will not live in it, and you have decent credit and some cash but not unlimited cash. Every section below moves that same deal one step forward and points you to the spoke guide that goes deep on each fork. By the end you should know what loan to ask for, where the down payment comes from, and what you will be tracking once the deal closes.

First fork: will you live in it?

The single biggest lever on your financing is whether you occupy a unit. If you moved into one side of the $250,000 duplex and rented the other, you would qualify as an owner-occupant, which opens FHA and conventional owner-occupied loans with far smaller down payments and better rates than any investor loan. That is the entire premise of house hacking, and the loan mechanics behind it sit in house hacking financing. On a duplex, an owner-occupied loan could put you in the building for a fraction of the cash an investor would need.

For the rest of this guide, assume you are not moving in. That makes the $250,000 duplex an investment property, and investment loans are a different animal: more down, a higher rate, and stricter reserves. The reason the rate runs higher is not a markup for spite; it is priced risk, walked through in why investment property rates run higher than your home loan. No rate numbers appear in this guide on purpose, because they move weekly and the mechanics do not.

Picking the loan type

For a non-owner-occupied duplex you have three realistic lanes, and they are compared head to head in conventional vs DSCR vs portfolio loans. The short version:

• Conventional investment loan. This underwrites you, not the building. The lender checks your debt-to-income, your credit, and how many financed properties you already carry, with a hard cap after the tenth. If your documented income qualifies you and you are under that limit, conventional almost always wins on rate, so it is the first thing to try on the $250,000 duplex.
• DSCR loan. This underwrites the duplex's rent instead of your income. The lender divides the property's net operating income by its annual debt payment, and if that ratio clears their floor, your pay stubs never come up. The full mechanics are in DSCR loans explained and the ratio itself in DSCR for rental property. You trade for it with a higher rate and often a prepayment penalty.
• Portfolio loan. A bank keeps this loan on its own books instead of selling it, so it can bend the rules: more properties, faster closings, looser docs. The trade is usually rate and term, and it shines once you are past what conventional will allow on the road from one to ten properties.

For the duplex, start by asking a conventional lender whether your income and property count clear their floor. If they do not, the DSCR loan is your next call, and its qualifying number depends on the rent you can actually collect, which is why you confirm rent before you buy with rent comps.

Where the down payment comes from

On a $250,000 investment duplex, a 25% down payment is $62,500, plus closing costs on top. The down payment thresholds across loan types are laid out in how much down payment you need for an investment property, and the closing costs that ride alongside it, with their tax treatment, are itemized in closing costs on investment property. That cash has to come from somewhere, and for most repeat buyers it comes from a property they already own.

• A HELOC on your home or another rental. A line of credit lets you draw the $62,500, deploy it into the duplex, and pay it back as the new property cash flows, without disturbing the low-rate first mortgage underneath. The math that has to clear is in using a HELOC to buy a rental property.
• A cash-out refinance. If you have a property with real equity, you can refinance it, pull out a lump sum, and use that for the duplex. The catch is you reset the whole loan, so it only makes sense if the rate you would be replacing is not far below today's. The LTV caps, seasoning rules, and costs are in cash-out refinance on a rental property.
• Seller financing. If the duplex's owner holds the paper, you can sometimes negotiate a smaller down payment and skip a bank entirely, covered in seller financing basics. It is rare, but worth asking about on a tired listing.

Whatever the source, do not drain yourself to the studs. After the $62,500 down and closing costs, you still need a cushion per door, sized in cash reserves for rental properties. A duplex with no reserves is one furnace away from a credit-card emergency.

How lenders count the duplex's rent

Here is the part that trips up first-time investor borrowers. On a conventional investment loan, the lender will count a portion of the duplex's rent toward helping you qualify, but not all of it and not at face value: they typically haircut it for vacancy and expenses before it offsets the new payment in your debt-to-income. Exactly how that works, and how it differs from a DSCR loan that counts the rent directly, is in how lenders count rental income.

The takeaway for the $250,000 duplex: do not assume both rents cancel out the mortgage in the lender's eyes. Run the deal on conservative rent and honest expenses, the way you would for any rental property analysis, not on the listing's rosy pro forma. The number you bring to the lender should match the property's real ledger, not a hopeful one.

What the financing choice does to your taxes

Financing is not only a closing-day decision; it follows you onto every Schedule E for the life of the loan. Each mortgage payment on the duplex splits three ways: deductible mortgage interest, non-deductible principal that builds your equity, and escrow that funds taxes and insurance. Only the interest is a deduction, and keeping the split straight is the difference between a clean return and a guess, walked through in tracking interest, principal, and escrow correctly.

The choice also shapes your equity story. Principal paydown on the $250,000 duplex is invisible in your bank account but real on your balance sheet, and it compounds quietly while the tenants cover the payment. That is one of the four ways a rental pays you, and it is the one financing creates. If you later wonder whether to refinance, sell, or hold, you will run the return on the equity you have built, which is the framework in when to sell a rental property.

After you close, track the loan

The financing decision ends at the closing table; living with the loan starts the next morning. From day one you are tracking an amortization schedule, the interest-principal-escrow split on every payment, and the equity that grows as the balance falls, and a duplex financed today will be on your books for years. Whether you use a spreadsheet, a shoebox, or software is your call, but you have to keep the loan's numbers honest because your NOI, your cash flow, and your Schedule E all lean on them. Check your assumptions against a cash-on-cash calculator and a cap rate calculator before and after you buy.

This is the part rents.ai handles for the loan you have taken out: it stores the loan, builds the amortization schedule, splits each mortgage payment into deductible interest, principal, and escrow, and tracks portfolio equity as you pay the balance down. It will not shop your loan, pull a live rate, connect to your bank, or tell you which lender to call; the financing decision and the application stay entirely yours. What it does is keep the loan correct once the deal is done. The whole purchase, from offer to your first month of records, comes together in how to buy your first rental property, and the bigger picture of holding several at once is in building a rental property portfolio.