Prefab ADUs 2026: Units, Permits and What They Earn
On published prices, the Boxabl Casita is the cheapest prefab ADU here at $60,000 for the unit and $150,000 turnkey. Abodu is the other maker that publishes an installed price, and its 500 square foot Abodu One comes to $324,800 with the foundation in. Abodu sells in California, where state ADU law requires rentals longer than 30 days for the units a city has to approve by right.
3 things decide a backyard unit that takes paying guests: the delivered price, how fast the permit comes, and whether the local ADU rule allows short stays at all. Every figure below comes from the maker's own page or a government page, checked on 4 October 2026.
The comparison table
Ranked on published price, lowest first.
Abodu splits its price in 2. The Abodu One is $260,800 for the home and $64,000 for installation. Its FAQ gives the 6 months and says it works generally in the San Francisco Bay Area and Greater Los Angeles. A $6,000 boundary survey, longer trenching, demolition and sales tax are quoted separately. Studio Home's terms are on its process page. Samara's 8 weeks and California availability are on its Backyard page.
Delivered price, line by line
- All-in. Abodu and the Boxabl turnkey price include the foundation, the crane and the utility connections.
- Unit plus installation. Samara and Studio Home publish the unit and leave installation to a quote. Abodu's own installation line is $64,000.
- Unit only. Dvele excludes delivery and onsite costs. Boxabl's turnkey price is 2.5 times its unit price.
Pre-approved plans and the 30-day permit
California wrote the shortcut into state law. Government Code section 65852.27 says each local agency "shall, by January 1, 2025, develop a program for the preapproval of accessory dwelling unit plans," and must approve or deny an application that uses a preapproved plan within 30 days of receiving a completed application. Read on 4 October 2026.
Seattle runs the same idea outside California. The city keeps a gallery of pre-approved detached ADU designs, and its permits page says "In most cases, you can get your permit in just 2-6 weeks" with a standard plan. Seattle's gallery holds designs by local designers and architects, so a factory unit is only pre-approved if that exact plan is on the list.
None of the 5 makers publishes a list of cities holding its plan on the pages we read. Ask for one.
Where the ordinance allows short stays
This is the check that can end a backyard Airbnb plan before it starts. A crane sets the unit in a day, and the ordinance does not move at all.
California. Government Code section 66323 covers the ADUs a local agency must approve ministerially. Subdivision (e) reads: "A local agency shall require that a rental of the accessory dwelling unit created pursuant to this section be for a term longer than 30 days." For other ADUs on single-family lots, section 66315 says a local agency "may require that the property may be used for rentals of terms 30 days or longer." Both read on 4 October 2026.
Portland, Oregon. The city licenses short stays in an ADU. Its Type A permit page, read the same day, limits a Type A rental to 2 bedrooms and 5 guests and says the bedrooms "may be located within a house, duplex, or in an accessory dwelling unit (ADU) or detached accessory structure." The resident must live in the dwelling unit where the bedrooms are rented for at least 270 days a year, and the permit lasts 2 years.
What they earn
The ADU math post puts a well-placed short-term rental ADU in a mid-tier market at $1,200 to $2,500 a month net, and works a payback on a $100,000 all-in project netting $1,500 a month, which is $18,000 a year and under 6 years. Those are that post's figures.
As an example only, put the Abodu One's $324,800 against the same $18,000 a year and the payback is 18 years. The Boxabl turnkey price of $150,000 is a little over 8.
What the table says
Price per square foot only compares units priced the same way. The Casita is $166 per square foot as a unit and $416 turnkey, so $250 per square foot of that home is ground work, shipping and crane.
An installation line runs to tens of thousands of dollars. Abodu publishes $64,000 on a 500 square foot unit. Samara and Studio Home publish none.
A fast install is a different number from a fast project. Samara's 8 weeks is time on site. Abodu's 6 months runs from contract to keys.
The rental term decides the revenue model before the unit does. Section 66323(e) requires terms longer than 30 days, while Portland permits short stays in an ADU with a 270-day residency rule.
Before you order
Work through these 3 in order.
- Read your city's ADU ordinance for the rental term. If it requires more than 30 days, underwrite the unit as a monthly rental. Start with the zoning rules guide.
- Price the ground. Run the lot through the site-prep cost estimator, then ask the maker for an installation quote in writing.
- Line up the loan. Read how to finance an ADU and start with the lender locator.
For what works once the unit is in, read the Backyard Playbook. For full-size prefab units, see the 8 best prefab cabins, rated.
Host Camp is not a licensed tax, legal or financial adviser. Confirm figures for your situation with a professional.
