How does New Jersey compare with the national average for an accessory dwelling unit (ADU)?

Homeowners in New Jersey typically recoup about 39% of the project's cost at resale, versus ~41% nationally. New Jersey is part of the Middle Atlantic Census division, which has the 3rd-lowest renovation resale returns of the 9 U.S. divisions.

What most affects the actual return in New Jersey?

Recency and condition. In Roots' model, work under 2 years old counts fully toward resale value, then depreciates toward ~20% after 10 years. A home with a documented maintenance record also typically sells closer to asking. Market conditions in the Middle Atlantic division set the regional baseline.

Where do these numbers come from?

Roots calibrates the national baseline for an accessory dwelling unit (ADU) against the 2025 Cost vs. Value Report (Zonda), then applies a Middle Atlantic-division adjustment derived from division-level averages in the 2024 Cost vs. Value Report, plus the model's own age and condition factors. Figures are modeled estimates, not appraisals.

Is an accessory dwelling unit (ADU) worth it in New Jersey?

Quick answer: Only partly, in dollar terms. In New Jersey, an accessory dwelling unit (ADU) typically returns about 39% of its cost at resale, below the ~41% national average. It adds real value, but treat it as an improvement you'll enjoy rather than an investment that pays for itself.

How New Jersey compares

New Jersey is part of the Middle Atlantic U.S. Census division, which has the 3rd-lowest renovation resale returns of the 9 divisions in Roots' valuation model. In practice that means an accessory dwelling unit (ADU) that returns ~41% of its cost nationally typically returns ~39% for a New Jersey home.

The same regional adjustment applies across the division (New Jersey plus NY, PA). Nationwide, the spread for this project runs from ~34% in the West North Central division to ~48% in the Pacific division. See the national breakdown for every region.

The Middle Atlantic market

The Middle Atlantic mixes dense, expensive metro markets around New York and Philadelphia with more affordable upstate and rural areas, and older row houses and colonials dominate much of the housing stock. In the pricier metros, renovated space commands strong premiums simply because buyers have limited move-in-ready inventory to choose from.

In supply-constrained metro markets, legally added square footage is one of the harder things for a buyer to find.

How other projects return in New Jersey

Project	Typical return in New Jersey
Accessory dwelling unit (ADU) (this page)	~39%
Wood deck addition	~78%
Bathroom remodel	~69%
Basement remodel	~67%
Window replacement	~63%

Return figures are typical resale-return estimates from Roots' home valuation model. Actual results vary by market, home, and workmanship, and shouldn't be relied on for lending, insurance, or tax decisions.

Sources: national baseline for this project calibrated against the 2025 Cost vs. Value Report (Zonda); regional adjustment derived from division-level averages in the 2024 Cost vs. Value Report.

Protect the value you add

Whatever the project returns on paper, condition decides what you actually get: in Roots' model the value of completed work fades as it ages, and a documented maintenance record helps a home sell closer to asking. If you're planning around resale value, start with upkeep. The free maintenance checklist generator builds a seasonal schedule for New Jersey homes in about a minute.

The bottom line

“According to Roots' home valuation model, New Jersey's Middle Atlantic region has the 3rd-lowest renovation resale returns of the 9 U.S. Census divisions. An accessory dwelling unit (ADU) there typically recoups about 39% of its cost, within a nationwide range of ~34% to ~48%.” — Roots home valuation model (regionally adjusted resale-return estimates)

Free tool Keep your home in the condition that holds its value The homes that hold their value are the ones that stay well maintained. Build a free maintenance checklist tuned to your home. It takes about 30 seconds and there is no signup.

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Frequently asked questions

Is an accessory dwelling unit (ADU) worth it in New Jersey?: Only partly, in dollar terms. In New Jersey, an accessory dwelling unit (ADU) typically returns about 39% of its cost at resale, below the ~41% national average. It adds real value, but treat it as an improvement you’ll enjoy rather than an investment that pays for itself.
How does New Jersey compare with the national average for an accessory dwelling unit (ADU)?: Homeowners in New Jersey typically recoup about 39% of the project’s cost at resale, versus ~41% nationally. New Jersey is part of the Middle Atlantic Census division, which has the 3rd-lowest renovation resale returns of the 9 U.S. divisions.
What most affects the actual return in New Jersey?: Recency and condition. In Roots’ model, work under 2 years old counts fully toward resale value, then depreciates toward ~20% after 10 years. A home with a documented maintenance record also typically sells closer to asking. Market conditions in the Middle Atlantic division set the regional baseline.
Where do these numbers come from?: Roots calibrates the national baseline for an accessory dwelling unit (ADU) against the 2025 Cost vs. Value Report (Zonda), then applies a Middle Atlantic-division adjustment derived from division-level averages in the 2024 Cost vs. Value Report, plus the model’s own age and condition factors. Figures are modeled estimates, not appraisals.

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