Looking for an affordable ADU, prefab home, or backyard house? Two very different options worth comparing are the Alltainer Haven 90 and the BOXABL Casita.
At first glance, both offer a factory-built alternative to traditional construction. But the similarities largely end there.
The BOXABL Casita is a compact 33,5 m² (361 sq. ft.) studio home designed around a standardized modular building system. The Alltainer Haven 90 is a much larger 90 m² (approximately 970 sq. ft.) three-bedroom home built using modified shipping containers.
That difference in size, construction method, transportation, customization, and price makes the two products suitable for very different buyers.
So which one is the better ADU?
In this comparison, we look at the Alltainer Haven 90 vs. BOXABL Casita across size, price, insulation, transportation, installation, foundation requirements, customization, construction time, durability, and permitting.
If you’re searching for an affordable ADU, prefab home, container home, or BOXABL alternative, this guide will help you determine which type of factory-built home makes the most sense for your project.
Alltainer Haven 90 vs. BOXABL Casita: Quick Comparison
| Feature | Alltainer Haven 90 | BOXABL Casita |
| Living area | 90 m² / approx. 970 sq. ft. | 33.5 m² / approx. 361 sq. ft. |
| Bedrooms | 3 bedrooms | Studio |
| Construction | Modified shipping container with insulated building system | Factory-built modular/SIP construction |
| Insulation | Up to R-60 with PU, depending on specification | Approximately R-23 walls and R-28 floor/roof, depending on specification |
| Transport | Standard container logistics | Specialized oversized transport |
| Foundation | Designed for support on 16 concrete blocks, subject to site requirements | Suitable foundation/support system required |
| Approx. stated factory price | From $39,000 | From $60,000 |
| Customization | High | More standardized |
| Delivery | Approximately 3–4 months, subject to configuration and availability | Depends on current production and availability |
| Typical use | Family home, large ADU, guest house | Studio ADU, guest house, backyard unit |
Prices, specifications, transportation, installation, and delivery times can vary by location, configuration, site conditions, and manufacturer availability. Foundation, permits, utilities, site work, and other project costs may be additional.
Quick Verdict
Choose the BOXABL Casita if you want:
- A compact 361 sq. ft. studio
- A standardized factory-built home
- An integrated kitchen and bathroom
- A small footprint
- A simple, predefined layout
Choose the Alltainer Haven 90 if you want:
- Approximately 970 sq. ft. of living space
- Three bedrooms
- A larger family-sized ADU
- More customization
- Container-based transportation
- A significantly lower factory price per square foot
Best for a compact studio: BOXABL Casita
Best for a larger family-sized ADU: Alltainer Haven 90
Best factory price per square foot: Alltainer Haven 90, based on the prices used in this comparison.
But the right choice ultimately depends on your property, local regulations, budget, and intended use.
1. Size: How Much Space Do You Actually Need?
The biggest difference between these two homes is size.
The Alltainer Haven 90 provides approximately 90 m² (970 sq. ft.) of living space. In its standard configuration, it can accommodate three bedrooms, making it suitable not only as an ADU but potentially as a small permanent family residence.
Alltainer also offers a smaller configuration of approximately 60 m² (645 sq. ft.), giving buyers an option between a compact studio and the full-size Haven 90.
The BOXABL Casita, by comparison, provides approximately 33.5 m² (361 sq. ft.) and is designed as a compact studio-style home.
BOXABL also offers configurations where multiple units can be connected to create a larger home, meaning buyers are not necessarily limited to a single 361 sq. ft. Casita.
That makes the size comparison more nuanced:
- BOXABL Casita: approximately 361 sq. ft.
- Alltainer smaller configuration: approximately 645 sq. ft.
- BOXABL connected configuration: larger multi-unit layouts
- Alltainer Haven 90: approximately 970 sq. ft.
Why does size matter?
A 361-square-foot studio can work extremely well for:
- A guest house
- A backyard office
- A rental unit
- A single occupant
- A couple
- Short-term accommodation
But if you want several bedrooms, a larger kitchen and living area, or a home suitable for a family, the additional space of the Haven 90 becomes significant.
Winner for space: Alltainer Haven 90
If you need multiple bedrooms and substantially more living space, the Haven 90 offers a very different proposition from the Casita.
2. Looking for a BOXABL Alternative?
If you’re researching the BOXABL Casita, you may also be looking for a BOXABL alternative.
The Alltainer Haven 90 approaches factory-built housing from a different direction.
Rather than focusing on a compact standardized studio, Alltainer uses modified shipping containers to create a much larger residential building.
This creates several important differences.
The Haven 90 offers:
- Approximately 970 sq. ft. of living space
- Three bedrooms
- A larger family-oriented layout
- Greater flexibility in configuration
- Container-based transportation
- A potentially lower factory price per square foot
The BOXABL Casita, meanwhile, focuses on compactness and standardization.
Neither approach is automatically better.
The better choice depends on whether your priority is a small standardized ADU or a substantially larger and more customizable home.
If you are specifically searching for a larger BOXABL alternative, the Haven 90 is worth considering.
3. Insulation and Energy Efficiency
Energy efficiency is an important consideration for any small or factory-built home.
A well-insulated building can reduce heating and cooling requirements, improve indoor comfort, and potentially reduce operating costs over the lifetime of the building.
The BOXABL Casita uses structural insulated panel construction. BOXABL specifications list approximately R-23 wall insulation, R-28 floor insulation, and R-28 roof insulation, depending on the specific construction and documentation.
The Alltainer Haven 90 takes a different approach.
The container structure is combined with an insulated building envelope using polyurethane insulation. Depending on the configuration, Alltainer states insulation values of up to approximately R-60.
The two systems therefore use different approaches to achieving thermal performance.
Winner for insulation: Alltainer Haven 90
Based on the maximum stated insulation specification, the Haven 90 offers a higher potential insulation value.
However, buyers should compare the complete building envelope and energy performance for their specific climate rather than relying on a single R-value.
4. Heating and Cooling
Both homes are designed to provide year-round residential comfort.
The Alltainer Haven 90 includes an HVAC system providing heating and cooling.
The BOXABL Casita also integrates HVAC into the factory-built home.
This is an important advantage of factory construction: major systems can be installed and tested before the building reaches the site.
When comparing homes, however, don’t just ask whether HVAC is included.
Ask:
- What heating system is used?
- What cooling system is used?
- What is the system’s efficiency rating?
- Is the system appropriate for the local climate?
- What electrical service does the home require?
- What maintenance will be required?
The answers can have a major impact on long-term operating costs.
5. Transport and Installation
Transportation is one of the major differences between the two systems.
The Alltainer Haven 90 is designed around standard shipping-container logistics.
Although the completed Haven 90 has an installed footprint of approximately 24.75 × 40 feet, the home is transported as a 40-foot shipping container and can use established container transportation infrastructure.
This is a significant advantage of the container-based approach.
The BOXABL Casita uses a folding modular design and requires specialized transportation when delivered to the property.
Site access is therefore an important consideration for both systems.
A home that looks inexpensive at the factory can become considerably more expensive if the site requires complicated transportation or installation.
Winner for transportation flexibility: Alltainer Haven 90
The ability to use established container logistics can provide an important practical advantage, particularly for sites where standard container transportation is readily available.
6. Foundation Requirements
One of the attractions of container-based construction is the potential for a relatively simple foundation.
The Haven 90 is designed to be supported on 16 concrete blocks, subject to the specific design, soil conditions, engineering, and local building requirements.
The BOXABL Casita also requires an appropriate foundation or support system.
The exact foundation required will depend on factors such as:
- Soil conditions
- Frost depth
- Wind loads
- Seismic requirements
- Drainage
- Local building codes
- Site-specific engineering
It is important not to confuse a simple foundation concept with “no foundation.”
The important question
Rather than asking:
“Which home has the cheapest foundation?”
ask:
“What foundation will my local building authority require for this particular site?”
That answer can vary considerably between locations.
7. Construction and Delivery Time
One of the biggest reasons people consider factory-built housing is speed.
Factory construction allows much of the building process to happen in a controlled environment before the home reaches the property.
For the Haven 90, Alltainer states a typical timeframe of approximately three to four months from firm order to arrival on site, depending on the specific configuration and project.
BOXABL has promoted rapid installation of its modular homes, but actual delivery timelines can depend on production schedules, configuration, site readiness, and availability. Buyers should request a current delivery estimate for the specific Casita configuration and location before making a purchase decision.
For that reason, buyers should request a current delivery estimate before making a purchase decision.
Winner: Alltainer Haven 90, when availability is confirmed
If the Haven 90 is available within its stated lead time while the comparable BOXABL configuration has a substantially longer production schedule, the Haven 90 may have a significant practical advantage.
8. Price: Don’t Compare Factory Prices Alone
At first glance, the price difference is significant.
Based on the prices used in this comparison:
- Alltainer Haven 90: approximately $39,000
- BOXABL Casita: approximately $60,000
But these numbers should not be interpreted as the final installed cost.
A factory price does not include:
- Transportation
- Foundation
- Site preparation
- Permits
- Engineering
- Utility connections
- Sewer or septic systems
- Water connections
- Electrical service
- Landscaping
- Local taxes and fees
- Crane or installation costs
The true number to compare is the total project cost.
Cost Per Square Foot
Using the stated factory prices alone, the difference becomes substantial.
The Haven 90 provides approximately 970 sq. ft. for $39,000, while the Casita provides approximately 361 sq. ft. for $60,000.
That works out to approximately:
Alltainer Haven 90: $40 per sq. ft.
BOXABL Casita: $166 per sq. ft.
On this simple factory-price comparison, the Haven 90 provides substantially more floor area for the stated purchase price.
9. Customization
This is another area where the two approaches differ.
The BOXABL Casita is intentionally standardized.
That is part of its appeal.
Standardization allows the manufacturer to produce a repeatable product and gives buyers fewer design decisions to make.
The trade-off is that there are fewer opportunities to completely redesign the building.
The Alltainer Haven 90 takes a more flexible approach.
Although the Haven 90 has a standard configuration, the container-based structure allows greater flexibility in room arrangements, finishes, windows, exterior treatments, and other design elements.
This can be particularly valuable if the home needs to fit a specific property or lifestyle.
Winner for customization: Alltainer Haven 90
If you want a home that can be adapted to your requirements rather than choosing a largely predefined layout, the Haven 90 offers greater flexibility.
10. Durability
Both systems can produce durable homes, but their structural challenges are different.
The BOXABL system is engineered specifically as a residential building. Its SIP-based construction is designed for residential structural performance.
Shipping containers are also extremely strong structures. They are engineered to withstand substantial loads during transportation and stacking.
However, modifying a shipping container changes the way the original structure behaves.
Large openings for:
- Windows
- Doors
- Connecting rooms
- Open-plan living areas
can remove portions of the original structural framework.
That means proper engineering is essential.
A container home should never be judged simply by saying:
“Shipping containers are strong.”
The relevant question is whether the modified structure has been properly engineered for the loads, climate, foundation, transportation and building requirements of its final location.
Alltainer’s Haven 90 is also designed for container transportation, with the modified unit maintaining the requirements necessary for container logistics. Meaning that the initial strength of the container is reestablished after modification to obtain recertification for seaworthy transport.
Winner: Alltainer Haven 90
Both approaches can produce durable homes when properly engineered, manufactured, installed, and maintained.
11. Permitting: What You Need to Know
For many ADU buyers, permitting is ultimately more important than the house itself.
A beautiful factory-built home is of little use if it cannot legally be placed on your property.
Requirements can vary significantly between jurisdictions.
Some locations have specific ADU regulations covering:
- Energy performance
- Foundation type
- Building code compliance
It is therefore risky to assume that a particular building is automatically “permittable everywhere.”
Instead, buyers should verify the requirements with the local authority before placing an order.
The right questions are:
- Does the proposed building comply with the applicable building code?
- What insulation requirements are applicable for my location
- What foundation is required?
- What engineering documents are required?
- Can the manufacturer provide the required documentation?
- What site-specific approvals are necessary?
This is one of the most important steps in the entire buying process.
12. Which One Is Better?
The better ADU depends on what you are trying to accomplish.
Choose the BOXABL Casita if you want:
- A compact studio
- A highly standardized product
- Minimal design decisions
- A small footprint
- A purpose-designed modular residential building
The Casita makes particular sense when simplicity and compactness are the priorities.
Choose the Alltainer Haven 90 if you want:
- Approximately 90 m² of living space
- Multiple bedrooms
- A larger family home
- Significant customization
- Flexible floor plans
- A container-based construction system
- Lower factory cost per square foot
- A home that can feel more like a conventional house than a studio ADU
The Haven 90 makes more sense when space, flexibility, and customization are the priorities.
13. What If 970 Sq. Ft. Is Too Much?
The choice doesn’t have to be between a 361 sq. ft. studio and a 970 sq. ft. home.
Alltainer also offers a smaller approximately 60 m² (645 sq. ft.) configuration, providing an intermediate option for buyers who want more space than a studio without moving all the way to the Haven 90.
BOXABL also offers larger configurations by connecting multiple units.
This means buyers should compare the right size for their property and lifestyle, rather than simply comparing the largest Alltainer model with the smallest BOXABL configuration.
The right question is:
How much space do you actually need?
If you need a studio, the Casita may be sufficient.
If you need two or three bedrooms, a larger Alltainer configuration may make more sense.
14. Why Is the Haven 90 Sometimes Called the “Casita Killer”?
Alltainer uses the phrase “Casita Killer” to describe the Haven 90 because the two products serve a similar broad market—people looking for alternatives to traditional construction—but offer dramatically different amounts of space.
The Haven 90 is substantially larger than a single Casita while maintaining a factory-built approach.
It also offers:
- More living space
- Multiple bedrooms
- Greater customization
- Container-based transportation
- A potentially lower factory price per square foot
But “better” depends on the buyer.
Someone looking for a 361 sq. ft. studio does not necessarily need a 970 sq. ft. home.
The real advantage of the Haven 90 appears when the buyer wants a full-size small home rather than a compact studio ADU.
15. The Bottom Line
The Bottom Line
The BOXABL Casita and Alltainer Haven 90 are not really competing for exactly the same buyer.
The Casita is a compact, standardized modular home designed to deliver a lot of functionality in a relatively small footprint.
The Haven 90 is a much larger container-based home aimed at buyers who want substantially more living space and greater flexibility.
If your goal is a 361-square-foot studio in the backyard, the additional size of the Haven 90 may simply be unnecessary.
But if you are looking for a three-bedroom, approximately 970-square-foot home, comparing the Haven 90 to the Casita becomes a very different proposition. The question is no longer simply “Which ADU is better?”
It becomes:
“Do I want a compact standardized home, or a much larger and more customizable home for a similar—or potentially lower—factory purchase price?”
For many buyers, that is the decision that matters most.
And before making that decision, always look beyond the advertised purchase price. Permits, transportation, foundation, utilities, engineering, site work, and installation can have a major impact on the final cost and timeline.
The best ADU is not necessarily the cheapest one or the largest one.
It is the one that fits your property, your budget, your local regulations, and the way you actually intend to live.
Ready to Explore the Alltainer Haven 90?
If you’re looking for an affordable alternative to traditional construction—and need more space than a compact studio—explore the Alltainer Haven 90 to see the floor plan, specifications, available options, and current pricing. Request current pricing and availability
[Explore the Alltainer Haven 90 →]
Looking for something smaller?
[Explore the Alltainer 60 m² option →]
Or if you’re still deciding which type of factory-built home is right for your property: