If you’re searching for the best prefab ADU for your backyard, you’re in the right place.

There is a severe housing shortage across the USA. Soaring property costs have made homeownership impossible for many or have forced people to move much further away to cheaper areas and work remotely.

Enter prefab ADUs.

They’re far more affordable and easier to build than traditional construction methods. They provide ultra-practical additional dwellings on your property (perfect for extra income if you live in a high-demand area), or they make awesome home offices.

But you need to make a sound decision about the prefab home you buy. You want high-quality, long-lasting construction at an affordable price.

I’ve spent the past few days delving into the world of prefabricated modular ADUs and narrowing the choices to the best ones available.

Below in this article, I’ll cover:

  • Everything you need to know about ADUs
  • What’s up with setting up an ADU in CA and LA
  • Budget options for those that want something under 100K

Ready to get started? Let’s go.

What Is a Prefab ADU?

prefabricated modular ADU
Image credit: AutonomousAI

An accessory dwelling unit (ADU) is the legal term for a secondary residential unit built upon an existing single-family lot.

The units are used to create additional dwelling space or provide homeowners with a means to create extra income through renting the space out—for example, a tiny house or home office.

ADUs are typically delivered in premade sections that need to be fitted together – a bit like Lego. The advantage of ADUs is that they are highly versatile, and the floorplans can be modified to fit almost any shape and size of space.

Additionally, these modular homes don’t require foundations and, therefore, don’t require a building permit. Plus, they take far less time (often just one or two days) and money to build than traditional constructions.

However, there are still codes and regulations surrounding the construction of an ADU, which differ from state to state. If you want to know more about the rules for your area, consult a local contractor.

Why Are ADUs in High Demand in California and LA?

Out of the top twenty areas where housing shortages are getting worse, seven of them are in CA. Los Angeles is particularly affected by a shortage of over 400,000 homes and a severe lack of affordable housing.

To help address the shortage and the soaring cost of existing properties, in 2021, the state relaxed its legislature around zoning ordinances and stipulations for ADUs, making it much easier to build them.

Unsurprisingly, since then, the demand for ADUs in CA has gone through the roof.

What are the Best Prefab ADUs?

I won’t keep you waiting any longer. Here’s my list of the very best prefab ADUs for under $100,000. High-end and affordable:

1. Autonomous StudioPod – Best Overall

Image credit: Autonomous

Size: 8.83 ft x 12.91 ft
Construction Material: Plywood, steel, and aluminum
No of Rooms: One
Price: Starting at $22,900

Striking the perfect balance between affordability and quality, the Autonomous StudioPod is a sight to behold.

The steel-built structure is super durable, while a honeycomb paper layer provides eco-friendly soundproofing and insulation. The black aluminum casing provides a weatherproof layer that looks sleek and modern.

The whole structure takes only one or two days to build and is designed to sit sturdily on all types of terrain.

Inside the living space, you will find a closet, desk, bookshelf, TV stand, a foldable coffee table, and a convertible sofa bed, so you don’t have to worry about finding furniture to fit. It’s all done for you.

The pod also features all the necessary power sockets, plus connections for climate control and electricity. The clever lighting comes with three color modes and mood lighting. Ideal for all occasions!

Oh, and you have huge windows for lots of natural light and for taking in the view. You’ll never want to leave!

The StudioPod has a one-year warranty and ships to all US states except Alaska and Hawaii.

📦 Learn more at Autonomous

2. Autonomous WorkPod – Best for a Home Office

The StudioPod
Image credit: Autonomous

Size: 8.58 ft x 11.87 ft
Construction Material: Plywood, hardwood and composite
No of Rooms: One
Price: Starting at $19,900

Autonomous make such good ADUs that we had to mention them twice!

If office space is your top concern, the WorkPod has you covered. The pod can stand on any terrain easily built in a few days.

Made from tough composite, the WorkPod is weather- and humidity-resistant. Thanks to its composite wood and honeycomb paper, the structure is energy efficient and very soundproof. Ideal for working in peace.

The WorkPod has a SmartDesk Connect standing desk, an ErgoChair Pro+, an anti-fatigue mat, a cable tray, a filing cabinet, and a dual monitor arm for maximum flexibility. Plus, you have plenty of power outlets and warm lighting for ultimate comfort and convenience.

For the price of less than 20k, it’s a steal.

Enjoy a one-year warranty and free shipping to anywhere in the US (excluding Alaska and Hawaii).

📦 Learn more at Autonomous

3. Boxabl Casita – Best Tiny House

Larger ADU
Image credit: Boxabl

Size: 19.5 ft x 19.5 ft
Construction Material: Steel, concrete, EP foam
No of Rooms: One but can be configured otherwise
Price: Starting at $50,000

Tiny houses are a fantastic way to create additional rental income, but they must be practical and comfortable.

Boxable offers one single square ADU model, but here’s the clever bit: You can stack and connect them in any way that you choose to create truly unique layouts.

And the really, really clever bit? The units unpack in an hour.

Yes, you heard right. They take one hour to construct. And thanks to the steel and concrete construction, they’re super sturdy.

Each unit features a full-sized, equipped kitchen, equipped bathroom, and a living/sleeping space with heating and air conditioning. Awesome insulation and LED lighting make this tiny home super energy efficient.

Additionally, it has stunning 8-ft doors and windows that allow plenty of natural light, and the unit is ADA-compliant, making it the perfect ADU for use as a tiny house.

Shipping is free to AZ, CA, NV, and UT; fees apply to other states.

📦 Learn more at Boxabl

4. Avrame USA Duo – Best for an Airbnb Rental

Unique ADU as a tiny house
Image credit: Avrame USA

Size: 20 ft x 20 – 40 ft
Construction Material: Wood
No of Rooms: Two plus loft and bathroom
Price: Starting at $50,200

To make your Airbnb guesthouse stand out, you must offer something special, and the Avrame Duo certainly does just that.

Featuring a distinctive triangular shape, the interior hosts a dormer and a loft, allowing for up to two sleeping areas, a living area, and a separate bathroom.

The strong foundational base and wooden truss construction are sturdy and weatherproof. The kit allows you to add insulation and choose your energy efficiency grade.

The interior finishes are left up to you so that you can customize them to your heart’s content. The price above includes the structure, shell, interior, and exterior kits, but you can take the customization further and opt for just the structure or structure and shell (and pay less in the process).

This ADU is perfect for creating a two-bedroom hideaway for vacationers. If you want a different size, this model is available as a one-bedroom or three-bedroom unit, too.

📦 Learn more at Avrame USA

5. Dwellito Kithaus K4 – Best Prefab ADU In California

two-bedroom ADU
Image credit: Dwellito

Size: 13 ft x 17.4 ft
Construction Material: Wood and aluminum
No of Rooms: One plus bathroom
Price: Starting at $59,500

Since ADUs in California are hot property (literally), it only makes sense to feature one specifically for this area. And the Dwellito Kithaus K4 only ships to California.

This gorgeous little unit features aluminum framing for stability and a slatted wood finish for that all-important shade. Low-e dual-glazed windows and structural insulated panels keep that fierce Cali sun and heat at bay.

The unit features a small bathroom with a shower and a kitchenette, plus the bright, airy living space will comfortably accommodate a sofa bed or generous-sized desk.

Other interior fittings, including the electrics, can be customized and upgraded to suit your budget and needs.

You’ll have the most stylish prefab ADU in the Golden State from the San Francisco Bay Area to San Jose!

📦 Learn more at Dwellito

What to Consider When Buying the Best Prefab ADU?

Just because it’s easier to build a prefab ADU, it doesn’t mean you should give it any less consideration than a traditional build. Here are some key things to consider when buying one.

1. How Many Square Feet?

Size always matters, so during the design process, you must remember what you intend to use the space for.

If you go too small, you’ll be frustrated by the lack of room. If you plan it too large, you’ll reduce your precious outdoor area too much.

Think carefully about the purpose of your unit and what furniture you need to fit inside, and create ADU plans to accommodate it comfortably.

2. Your Budget

Here’s where you must be careful. While the base price of prefab ADUs can be highly attractive, installation costs can significantly raise the price. Hiring home builders to do the job can also be expensive.

Also, factor in the cost of any upgrades, the shipping price, and how much it will cost to connect it to the utilities.

Also, consider running costs and include sustainability factors if the budget allows. For example, installing solar energy may cost more upfront but will save you a tonne in the long run.

3. Local Building Codes

While prefab ADUs don’t require a building permit to construct, they are subject to your local zoning ordinances and stipulations. These differ from state to state, so research before starting the project.

The Best Prefab ADU FAQs

What Are the Benefits of Prefab ADUs?

There is a whole heap of benefits to adding a prefab ADU to your property. Notably, it can:

  • Increase your home’s value by up to 30%
  • Provide an additional source of income by renting out the unit
  • Add additional space to a family home
  • Create a customized space perfect for your requirements
  • Be up and running in a much shorter timeframe than a traditional build
  • It costs far less than a traditional build

How Many ADUs Can a Person Build in Los Angeles?

If you have a decent-sized backyard, you will be thrilled to learn that the state of California recently relaxed its rules around building ADUs.

The law stipulates that you are allowed to build up to two prefab ADU units on your lot as long as you have the space for them, of course.

What Qualifies as an ADU in California?

An ADU in California can be up to 800 square feet in floor space and up to 16 feet in height. There must also be at least four feet of side and rear yard setbacks.

The unit must also include a separate entrance to the main dwelling. It must have a bathroom, kitchen, and at least one parking spot to be used as a residential unit.

Newly constructed ADUs must also be fitted with solar panels.