What NH rents actually run
New Hampshire Housing's statewide survey put the median 2-bedroom gross rent at $1,833/month in its 2024 survey — up 36% since 2019 — and its October 2025 report shows medians of $1,668 (1-bed) and $2,024 (2-bed). Market listings run higher in our core towns: Dover's median 1-bed is $1,825 (July 2026). And vacancy is the real story: NHHFA measured 0.8% statewide vacancy against the ~5% of a balanced market — NH simply does not have enough rentals.
Against those medians, our modeling below is deliberately conservative: at $2.25–$3.00/sf, a 384 sf 1-bed models at well under Dover's published median — brand-new construction typically sits at the top of any town's range, not the middle.
The assumptions (printed, not hidden)
Financing: construction-to-perm at 7.25%, 30-year term, 25% down — the standard NH bank product for new ADU builds. Rent: $2.25–$3.00 per sf monthly for new construction, at 95% occupancy (long-term tenant). Change any of these on the live calculator on any model page.
Payment vs rent, all ten models
| Model | All-in price | Monthly payment | Expected rent | Net cash-flow / mo |
|---|---|---|---|---|
| Barrington 384 sf · 1 bd | $184,000 | $941 | $821–$1,094 | −$121 to +$153 |
| Wakefield 525 sf · 1 bd | $269,000 | $1,376 | $1,122–$1,496 | −$254 to +$120 |
| Newfield 600 sf · 1 bd | $244,000 | $1,248 | $1,283–$1,710 | +$34 to +$462 |
| Summit 654 sf · 1 bd | $293,000 | $1,499 | $1,398–$1,864 | −$101 to +$365 |
| Rye 750 sf · 1 bd | $348,000 | $1,780 | $1,603–$2,138 | −$177 to +$357 |
| Shapleigh 800 sf · 2 bd | $313,000 | $1,601 | $1,710–$2,280 | +$109 to +$679 |
| Spruce 882 sf · 2 bd | $361,000 | $1,847 | $1,885–$2,514 | +$38 to +$667 |
| Washington 896 sf · 2 bd | $380,000 | $1,944 | $1,915–$2,554 | −$29 to +$609 |
| Ella's Retreat 981 sf · 2 bd | $401,000 | $2,052 | $2,097–$2,796 | +$45 to +$744 |
| Ossipee 1049 sf · 2 bd | $483,000 | $2,471 | $2,242–$2,990 | −$229 to +$518 |
Principal & interest only, at the printed assumptions. Estimates — not a loan offer, a rent guarantee, or financial advice.
The costs most calculators skip
Honest math includes the carrying costs beyond the loan payment: property tax on the new unit (it gets assessed — ask your town's assessor for the rate), insurance (your policy grows to cover the second structure), maintenance (budget ~1% of the build cost per year — less early on for new construction under a 5-year warranty), and vacancy (we already haircut rent to 95%). Even with all four, mid-size models at mid-range rents typically stay comfortably positive — but run your own numbers with your town's tax rate before you commit.
Beyond the monthly check
The cash-flow is only half the return. The other half: the unit itself is an asset on your land — new-construction square footage added to your property at a known, contracted cost — plus the optionality that comes with it (family housing later, aging-in-place, sale appeal to multigenerational buyers). The in-law suite guide covers that side of the math.