We’re in the market for a new house/rental property. A friend of ours passed along a community for us to look into. I figured it’s worth showing our evaluation approach (OK, it’s my evaluation approach. My wife is much more interested in the big picture rather than how the math is done).

The community is in Fulton, MD. (Montgomery county for those of you that read my last post on growing counties in MD). Fulton is a planned community under construction. It has a Town Center with a community area complete with exercise facilities, a pool, and common spaces. There’s a mix of neighborhoods, ranging from apartments, condos, and townhouses to single family “estates”. The community is in the southern part of Howard County MD, so it definitely checks our box for good schools.

In a previous post, I talked a bit more about our requirements. So, I’ll talk more about the math of evaluating a mixed use rental property where we live in one part, and rent out another. While we’re not explicitly looking for a duplex, that’s essentially how I’m approaching this topic. Here’s two of my favorite bloggers weighing in on general rental property evaluation: Afford Anything, and Financial Samurai. Finally, here’s an article specifically about duplex investing on bigger pockets, one of the biggest real estate blogs out there.

Let’s start with cash flow. For a typical owner *un-*occupied property, cash flow must be positive to even think about moving forward (rents must be higher than expected costs). For your personal residence, total costs should be less than some % of your gross income. For better or worse, we’re looking to blend the two. See how this seems different: we’re looking to buy a place with a portion of the costs offset by a renter. If it was a classic duplex, we’d likely want to “live for free” such that the renter covers not only their portion of the costs but 100% of ours as well. Somewhere between “live for free” and rents subsidize our lifestyle is the trade space we’re looking into.

With that said, the math ends up being pretty straightforward. Here’s a link to the spreadsheet I’ll be using to evaluate potential properties that fit into this kinda-sorta-duplex.

- We can estimate what an individual property will cost us to own and operate/maintain as our primary residence.
- We can estimate market price point for a rental property that looks like ours.
- We can subtract the two to find out what our net cost of living will be.

Next, appreciation. Zero (this one is easy). I never assume we’ll benefit from any appreciation on a rental property. There’s some good reasons for this: real estate tends to appreciate with inflation. This keeps the math simple when evaluating prospective properties, and keeps me conservative.

Finally, taxes. I figure out what the estimated property taxes will be so I can factor them into cash flow. The source foe the tax information is either based on the listing (if available) or the historical tax records…You know those are all public records, right? Here’s the MD website. And, here’s a link to an online public records search site so you could look start your search anywhere in the US. After that, any deductions, expenses, etc are all gravy. I would never advocate buying a rental property just because of the tax benefit. The underlying investment needs to be sound first.

So, how does Fulton stand up?

Here’s a nice 4 br/2.5ba single family home in this area. It’s not built yet, so there’s some opportunity to increase costs. Let’s just assume we stick to the builders “vanilla” house and get all 2894 sqft for ~750k (yowza)! Median rents for a 1br/1ba are ~$1,900/mo. Let’s assume that the HOA will take kindly to us turning this into a duplex. Then, let’s run the numbers based on the information in the listing:

Let’s start with the biggest red number on the sheet: $168,747.75. Say it with me: one hundred sixty eight thousand, seven hundred forty seven and seventy cents. If we were to put 20% down, that’s the amount of cash we would need for the down payment and for estimated closing costs. Ouch! Next, that big number to the right of Monthly Recurring Costs: $5,612.19. Every month for ~30 years we would owe, escrow, insure, or maintain this sum in order to afford this lovely home.

Now the good news. A 1 br/1ba in this neighborhood is also a pricey affair. I saw $1,900/mo as the nominal rent for such an apartment. So long as we don’t mind neighbors downstairs indefinitely, we could end with a net monthly cost of $3,468.19. That’s still a big number, but it helps to illustrate why I’m so keen on having a rental property baked into whatever becomes our next home. Note that I took a wild guess to arrive at ~20k to convert part of the basement into a rental unit. Here’s hoping that’s in the realm of reasonable! Because these numbers are still ~~pretty~~ big for us, I’m leery of making this kind of commitment without doing some serious homework.

What do you think? Would you ever accept a long-term rental situation in order to afford a big honkin’ house? Is there another way to make this kind of move and keep it affordable?