What an ADU actually costs in Maine & New Hampshire in 2026
Langone Site Services turn-key ADU pricing in 2026 ranges from $147,000 for The Bean (384 sq ft) to $388,000 for The Ossipee (1,049 sq ft with a 2-car garage). These are starting numbers on a standard site - not estimates that grow once permits start. Town tap fees and major site issues are quoted separately.
The ten published models and their starting prices
- The Bean - 384 sq ft, 1 bed, 1 bath, 16×24, one story - from $147,000. Tight-lot guest cottage, first rental, or in-law suite.
- The Wakefield - 525 sq ft, 1 bed, 1 bath, 30×18, one story - from $216,000. One floor, between The Bean and the 600-foot class.
- The Bentley - 750 sq ft, 1 bed, 1 bath plus attached garage - from $278,000. Existing Langone garage model. ZIP-system shell, granite, Mitsubishi mini-split.
- The Newfield - 600 sq ft, 1 bed, 1 bath, 30×20, one story - from $196,000. Value 600-foot plan without a garage.
- The Summit - 654 sq ft, 1 bed, 1 bath, 30×22, one story - from $235,000. Next size up when you want more open living on one floor.
- The Shapleigh - 800 sq ft, 2 bed, 1 bath, 40×20, one story - from $252,000. First 2-bed in the lineup.
- The Spruce - 882 sq ft, 2 bed, 2 bath, 42×21, two story - from $290,000. Two full bathrooms.
- The Washington - 896 sq ft, 2 bed, 1 bath, 32×28, two story - from $305,000. Slightly larger than The Spruce with one bath.
- Ella's Retreat - 981 sq ft, 2 bed, 2 bath, 36×28, one story - from $321,000. Largest one-story 2 bed / 2 bath we publish. Ella's Retreat needs a town that allows that size.
- The Ossipee - 1,049 sq ft, 2 bed, 1 bath, 38×28, two story plus 2-car garage - from $388,000. Largest published model. The Ossipee needs a town that allows that size.
What's included in the turn-key price
Every ADU package includes:
- Monolithic slab foundation, excavated and poured
- ZIP wall + roof sheathing with 30-year architectural shingles
- Matthews Brothers Windows & Doors
- Vinyl siding in your chosen color
- Mitsubishi mini-split heating and cooling
- On-demand hot water
- Starlink internet setup (rural connectivity ready out of the box)
- LVP flooring throughout
- Tongue-and-groove pine ceilings
- Hardwood cabinets with granite counters
- Delta plumbing fixtures
- Recessed LED lighting
- R49 ceiling + R23 wall insulation
What can push price above the starting number
Site conditions and town tap fees can change the number. If the lot needs its own system, Maine conventional septic starts at $18,000 and Maine design starts at $700. Town permits vary.
Why a starting price can sit on the page
Because the models are standard, the real costs are known before the first site visit. That is the only reason a figure can be published here rather than held behind a design retainer.
A range for your own lot takes about two minutes in the instant pricing calculator, which runs on 2026 job figures rather than on a rule of thumb.
Or book a free 20-minute land or build consult with Dylan directly.
The 2-minute calculator is on instant pricing. Published packages are on the ADU models.