Real Estate Agent · Boston, MA · Member since 2025 · 42 posts · 16 votes
New Hampshire needs an estimated 60,000+ more homes, and as of August 31, 2026, HB 1079 requires towns to allow ADUs converted from structures that existed on or before July 1, 2025 (RSA 674:72). On paper, that's thousands of garages, barns, and carriage houses that just became legal rental units.
Meanwhile the market isn't waiting: September NH single-family inventory was up 19.3% year over year (3,164 homes for sale), the median price still rose 6.5% to $569,900, and months of supply sits at 2.9 — more choice, but still a seller's market.
I'm a Realtor licensed in NH and an investor/operator (17 units across MA), and I just helped a buyer close in Nashua this month — so I'm looking hard at southern NH. The question I keep running: at today's construction costs and ~7.4% money, does an ADU conversion actually pencil, or is this a paper win?
If you've priced or built an ADU conversion in NH this year — what did the all-in cost per unit look like vs. the rent you can get? And how are towns actually handling approvals under the new law?
A new law can open a door without making every conversion pencil, so I would price it as a project, not a policy win. The state rule may allow the unit, but the town’s process, the site conditions, and the all-in cost still decide whether it works.
I would build the budget from the ground up: permits, utility connections, egress, insulation and code items, parking, and any septic or sewer work, plus a contingency for surprises in an older structure. Then compare that total, with financing costs, to a supported rent for a unit of that size and location, not to a best-case rent.
I would also confirm the local interpretation early, including timeline, inspection steps, and whether the unit can be rented separately as planned. If the project only works with a low construction bid and a high rent, I would treat it as fragile and keep looking for a version with more margin.