Non-Toxic Eco Prefab Homes Compared

Partially Updated in 2023, Updated for Substack in 2025

This list focuses on non-toxic prefabricated (“prefab”) homes.

They must be both mold-preventative designs and low-VOC to be “healthy homes” in my book.

I have reviewed them myself with input from customers and building science experts. Many need further closer inspection.

When considering a prefab, it’s important to see the detailed design of the build and see pictures of their builds in progress, and if possible,

They must be willing to work with a mold-aware architect. Some companies have their network of installers and some rely on you having your own builder.

Many will turn down severely chemically sensitive clients; I recommend bringing me onto the team before getting into materials with them to avoid that scenario.

I look through what you need to know about the process of building a prefab and make sure the materials are safe and the design is mold-preventative on Substack – Steps to Building a Healthy Prefab, Good Signs and Red Flags, Pros and Cons of Building Prefab, Building Prefab with Environmental Sensitivities.

Building a home, even if prefabricated partially or fully offsite, is still a complicated process to navigate.

This post focuses on standard-size homes, though some make models in the 400-500 sq ft range.

If you are looking for smaller and more affordable homes, my series on small and simple homes covers those.

This post contains no sponsored or affiliate content, and I don’t have a partnership or other ties to any of the companies listed.

Review of Non-Toxic Prefab House Companies

1-3

My top three choices for non-toxic prefabs are in this Substack article.

4. Morton Metal Siding Structure

https://www.instagram.com/p/Bvb4gS2gM68/

This company makes fairly standard construction metal siding homes and structures and has been reviewed by Cheryl Ciecko. They have worked with her and they are willing to work with her again to make sure it’s designed right.

Process

With the Morton process, many materials are manufactured in their plants (which they own—this is a large company). Building components are shipped to the job site using their trucks. Construction is executed by their construction crews—vet your local crew well.

Construction management is provided by them—again, vet the local management well. This is a design-build firm, which means they take care of the whole process.

They use Allied Design Architectural & Engineering Group, but they will allow your architect to have input on the plans.

Design & Materials. This is a conventional build; it’s not high-performance or Passive House. It’s stick framing, regular insulation, metal siding, and drywall. There’s nothing especially unique here other than they are willing to work with Cheryl.

Established. It’s a well-known brand, around since the 1940s with a robust warranty and little risk of the company going out of business soon.

Factory. They are fabricated in Morton, IL.

5. Holz100 All Wood Houses

https://www.instagram.com/p/Bz-y6YYjJl3/

This panelized and module prefab is something a little different. This company makes panels that are made from all wood: walls, ceilings, and floors. No adhesives. No nails. Just wood. Siding and roofing materials might not be wood.

They claim a 50-year warranty on condensation and mold in the walls. The company has not been in business for 50 years though, about 25 so far.

The next step here would be to see if a building science expert (actually, more than one) can look at this wall system, which is a series of pieces of wood with some air gaps, and see what they think about moisture management in that type of wall.

I would also like to see computer modeling of moisture in the walls, and why it doesn’t hit dewpoint in those spaces, or real-life data from the company showing how moisture performs in the walls.

I want to know how they deal with the roof since it looks like they are putting an exterior vapor barrier on the flat roofs that could get tricky for mold fast. The underbelly of raised-up wood houses can also be vulnerable to condensation.

If this system holds up the way it says it does, it will be a very interesting option.

I am really rooting for this company, as I think it looks really cool.

Although I’m reluctant to be a test person for something we don’t know enough about I was happy to see Matt Risinger tour this style of home (a company called Holzpur. With the green light from both Matt and SIGA (who sponsored the video), it would make me want to proceed with the next steps of review.

Geographical Area

Most of their buildings are in Europe and you could go see some of the buildings there, including a hotel in Austria, a hotel in Belgium, and a rental. That would be crucial as well, to see how this is holding up in real life. And you can sleep there to see how you feel.

They are also available in the US and Canada.

Cost

The small little room that is just under 100 sq ft is 35,000 CAD.

A tiny house is 39,000 Euros. They make houses of all sizes, including apartment complexes and hotels.

6. GO Logic GO Home

https://www.instagram.com/p/B4fr_hAg4Xt/

These are Passive House-level panelized prefabricated homes.

This is another highly respected company. They are a design-build company in Maine.

Outside of Maine, they assemble the shell only. Your local contractor does the rest.

Materials and Design

2×8 wood stud wall. Dense-pack cellulose insulation in the stud cavities. Rigid mineral wool insulation between the sheathing and siding.

Taped Huber Zip OSB air barrier. See my post on pressed wood products to review the offgassing of these materials.

The roof is made with prefabricated wood trusses with blown-in cellulose insulation. See my post on insulation.

You can choose from many different design options. Windows are aluminum/PVC or aluminum/wood (triple glaze).

Flooring is concrete and real wood, Marmoleum or tile.

They use high-quality finishes like solid wood stair treads and solid wood trim. Interior walls are gypsum with 0 VOC paint. IKEA cabinets.

You can upgrade or change most of these interior finishes.

Moisture Management

They use meticulous air-sealing between the attic and living spaces and ventilation beneath the sheathing to eliminate the risk of moisture buildup and ensure a durable roof.

They seal the critical joints at window openings, between the foundation and exterior walls, and between the wall and roof structures.

Wall assembly is designed to avoid moisture build-up.

They use mechanical ventilation – HRV. Electric heat (like most Passive Houses).

On-site blower-door testing meets or exceeds Passive House standards.

Costs. Size is 600-2500 sq ft from $179,000 to $567,000.

How long have they been in business? Go Logic (founded 2008) company launched the GO home prefabs in 2017.

Geographical area. Delivered and assembled in Maine. Outside of Maine, they deliver the shell only in New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, or eastern Pennsylvania. Your local contractor would provide the site work, exterior, and interior finishes.

7. BrightBuilt Homes

An updated review of this company in 2025 is in Substack.

Please note, I’m not recommending this company.

BrightBuillt appears at first to be a competitor of Ecocor and GoLogic.

They make net-zero-ready homes that are a bit better than code.

The house arrives in modules as opposed to panels.

Materials

Double-stud walls insulated with dense-pack cellulose. It looks like fiberglass in the roof in some pictures. Some have rigid insulation on the exterior.

Moisture-Management

Air sealing, some use Zip system, some use Blue Skin or Typar. Drainage plane below siding, mechanical ventilation. They have pictures of blower door tests, but it’s not clear if they test all of them.

The lack of information on materials, cross-sections of the walls and ceiling, and details on building science on the website is a red flag for me.

Customer feedback

I spoke to someone that built with them and those details are in the Substack.

Process

You have three primary routes you may choose: a pre-designed BrightBuilt Home (from 9 models), a modified BrightBuilt Home, or a custom home.

If you are happy with one of the standard designs, you will simplify the pricing. If you would like to make some modifications to the existing designs, you can make changes to the finishes, spaces/interior design. Or do a totally custom design.

They help you identify a builder.

BrightBuilt designs the modules, passes it on to a company that makes the modules. The builder is responsible for all on-site work.

Factory. Subcontracts the manufacturing of their panels/modules out.

Established. They have been in business since 2013. Their parent company (architectural firm) has been around since 2004.

Geographical area. At this time, they construct, deliver, and complete within Maine and the Mid-Atlantic region.

8. Module Homes

This company has changed significantly since I first wrote this article in 2020, an updated look at this company is in Substack.

https://www.instagram.com/p/B601GTCBh7p/

Module uses both wood-based panelized and modular construction. Their houses are built off-site at the Bensonwood Tektoniks factory.

Their first home, the Latham house, was built to Passive House standards. In the future, all of the homes will be built to the Zero Energy Ready Home standards.

Geographical area. Based in Pittsburgh, modules are made in New Hampshire, they deliver to any area of the US. 

This is a design-build firm: they manage everything “from the first shovel to the last coat of paint”, they claim.

Materials

Zip panels with cellulose insulation.

The base model option has fairly standard materials (like IKEA cabinets and laminate countertops). The upgraded options have healthier materials like custom cabinets and solid surface countertops.

Factory.

Tektoniks factory is owned and operated by Bensonwood; it’s not owned by Module.

The companies design the panels and send the design specs there to be made.

Cost. One of their two-bedroom homes is $250,000. An estimated 50K more for site work, foundation, and permits.

How long have they been in business? Since 2017.

You can see a video of their first house here:

9. Log Cabin Kits

https://www.instagram.com/p/BxgFZ5Ljb9H/

Although log cabins don’t have a lot of insulative value, and they don’t completely skip past the need for intricate detailing, I like the simplicity of solid wood walls with nowhere for moisture to accumulate and hide (in theory).

The logs need to be debarked and stored properly in good mold-free conditions before the build.

And, as always, pay special attention to the roof and foundation which are done wrong in almost all assemblies, whether it’s in the design or execution. Most foundations have water damage.

They are prone to moisture damage in cold climates. Around windows, doors, and building corners are vulnerable areas. Thermal mass improves the performance a bit, but air leakage more than counters any benefit. Cool surfaces + a source of moisture = mold.

You still want to have this evaluated by a building science expert to see how log walls will perform in your climate and hold up to moisture and mold.

You also want to evaluate the companies based on their specific “log” system. As these walls are usually square or rectangular, not the classic real round logs.

I mention a few companies that look good here.

10. Method Homes

https://www.instagram.com/p/B5qe0Y3AJUf/

Method makes modular homes that can reach Passive House standards.

Method will build anything an architect designs, as long as it can still be shipped.

Process. You can use their design-build company, Method Contracting, or go with a local builder or general contractor of your choice (“under our direction,” they say).

Method has an internal team of specialists and they have an external network of contractors throughout the Pacific Northwest (the US and Canada) that they can recommend and work with.

They don’t say quite as much on the website about building science as the others, but they do say they avoid thermal bridging through either double-stud walls, rigid foam wrap, or a combination of the two.

They do blower door tests to measure airtightness. In order to achieve a very tight envelope, they use the specialty (high-performance) tapes like those used to seal the seams of the plywood during framing.

They also use ‘flash and batt’ which is a very tricky method to get right, explained here. I don’t use spray foam in walls due to off-gassing concerns as well as technical difficulties.

They use ERVs or HRVs for ventilation.

This has been reported to be highly customizable.

Materials. Real hardwood floors, 0 or low VOC paints, and glues. In a message, a company rep said, “While we use no VOC products, we are not fully set up to build homes for the environmentally sensitive community”.

Area served. Method has experience delivering and building in challenging and remote sites, including the San Juan Islands and British Columbia Islands.

Their manufacturing facility is located in Ferndale, Washington. They service the western US and Canada including Washington, Oregon, California, Alaska, Idaho, Montana, Wyoming, Nevada, Colorado, Utah, Hawaii, British Columbia, and Alberta.

Cost. Base price $162,000.

11. Artisans Group

https://www.instagram.com/p/BeFD8D9AjHr/

Artisans Group is a design-build firm in the Pacific Northwest. They build prefabricated panelized homes to Passive House standards. They can do custom designs or you can choose from their pre-designed plans. I had to email them to clarify: any in their current portfolio is a predesigned plan.

They work with their network of selected prefabricated Passive House builders who deliver the floor, wall, and roof assembly systems to your site.

They use the design-build model because communication between the design team and the construction team is extremely important in order to get things done right.

The assembly is overseen by a Passive House expert.  

Year Established. They are a large firm, in business for 20 years. They claim they have designed more homes to the Passive House Standard than any other US firm. (Ecocor makes the same claim).

They have a good team that is highly educated on building Passive Houses.

Materials. They have been using low and no VOC finishes since the days you had to special order them. (Another good sign they know materials well).

There is not a lot of detailed information on the website about the wall assembly and design. Like all Passive Houses, they do use HRVS (air exchange). I would make sure you can find out more before committing.

12. Phoenix Haus

https://www.instagram.com/p/BpPi1p9g3hV/

Phoenix Haus is a panelized system that is Passive House certified.

Design & Materials

The Phoenix Haus Alpha System is lightweight timber frame construction, insulated with cellulose, mineral wool, and wood fiberboard. The system uses solid timber supports with timber I-beams in the roof. With a ventilated rain screen on the exterior.

An airtight membrane (Intello Plus) is used on the inside of the supporting joists (behind the service cavity). Tescon Vana tape is used on joints. The exterior water-resistive barrier is Solitex.

These are all low offgassing (or practically 0), very common Passive House materials. Most passive houses use these same membranes and tapes.

They do show the cross-section of the designs, which is important information to have.

Geographical area. They can work anywhere from the Midwest to the Rocky Mountains and Pacific Northwest.

Process

Phoenix Haus does the architectural drawings, makes the panels (the panels come with windows and doors), and they deliver them to the site.

The company assembles it and helps you find a builder from their network. You can also choose your own builder.

The general contractor does finishing work (mechanical, electrical, plumbing, flooring, drywall, etc.).

They are open to working with your architect.

Year established. Phoenix Haus has been in business since 2011.

Cost. A 1,500 sq ft cabin costs about $150,000, which usually totals $375,000 with finishes, excluding land and design fees.

They have no pictures of completed houses on their website or Instagram, which seems very unusual to me.

13. EcoCraft

https://www.instagram.com/p/Bf8joQzHvYW/

EcoCraft uses prefab building techniques, but the houses are all custom-designed. They build in modules, as opposed to panels. They can be Passive House certified.

Process. They work with local architecture firms. This sounds like they don’t have an in-house architectural team.

They take care of all the building (and the cost includes this): basic excavation, an unfinished basement, walls, roof, finishes, plumbing, electrical, appliances, delivery, installation, and all finishes if you are in the Pittsburgh area.

Materials and Design. They use continuous exterior insulation (rigid foam). Like all Passive House homes, they are built airtight, with a heat recovery ventilator.

They use un-faced formaldehyde-free fiberglass batts within the walls and floors, and blown fiberglass in the attics, along with spray foam insulation to seal air leaks. (You will want to see how much spray foam is used and what kind.)

Fiberglass is a step down from Rockwool/mineral wool.

They use thermal imaging and blower door testing to test for air leakage (which leads to vapor movement).

On the interior, they use low or no-VOC paints and low or no-VOC adhesives and sealants.

Factory. The modules are manufactured in a factory located about 90 miles out of Pittsburgh.

Geographical area. They are based in Pittsburgh and build within a 60-mile radius of Pittsburgh. Sometimes, they build outside that radius, or you can use the panels outside of the radius, but they will not be able to complete the build.

Warranty. They carry a 10-year structural warranty and 1-year cosmetic warranty.

Cost. EcoCraft Homes start at $285,000.

14. Bamboo Living

https://www.instagram.com/p/BudE2i5HH_D/

This Hawaii-based company makes panelized bamboo homes. They have insulated walls and uninsulated wall options.

When going with a traditional indigenous building technique, keep it close to the original way of building. Bring in current experts in building science to analyze it, as well. That means no insulation for me with bamboo.

Bamboo is a traditional building material in a huge part of the world. This leads me to believe there is a way to build this in a mold-preventative way.

But, bamboo being bamboo (quite the finicky material with moisture), probably means there are a thousand ways to mess this up. That means more research is needed here than usual.

I personally would not ship bamboo panels very far from where they are built.

Warranty. They give a 20-year structural warranty.

Tour: You must check out other bamboo buildings first, including a hotel made by this company.

Year Established. They have built 400 homes they say. The company started in 1995.

Cost. Base price of $89,000

15. Plant Prefab Living Homes 

https://www.instagram.com/p/BqptxXmll1F/

LivingHomes is Plant’s in-house design studio. I’m mentioning this company because it’s usually on non-toxic prefab lists, not because I’m particularly impressed.

Materials

The construction is standard. From what I can see, they use OSB, Knauf Ecobatt fiberglass insulation, and regular drywall. They use exterior rigid foam insulation, house wrap, furring strips, and James Hardie siding.

They use Anderson Windows (you can upgrade to aluminum windows). Doors are by Thermatru, flooring Millstead Cork Floors, kitchen/bath cabinets by Merillat Cabinets.

They claim to be low VOC by using 0 VOC paints and stains, millwork, and engineered wood without (added, I’m assuming) formaldehyde, no wood-burning fireplaces. Vents in the bathroom—every house should have a vent in the bathroom, so this should not be their main claim to fame on mold prevention!

These materials are all very standard and any builder can build with these.

They say they include indoor plants to absorb “dangerous compounds”. This is a big red flag for me for greenwashing and lack of knowledge about VOCs, as these plants do almost nothing.

Process

They can work with your architect to create a custom design, or you can choose from one of their standard designs.

You can find your own contractor or they can help you find one.

They coordinate with the general contractor in charge of site work and foundation; they resolve any design issues and maintain oversight and quality control during the construction process. This is good: if they have this much control over the process, assuming they know what they are doing, oversight is good. A clean line of responsibility between parties is good.

Factory. All Plant Prefabs are built in their factory in Rialto, California. You can visit the factory and see your home being built. (I like this part.)

Warranty. In addition to the standard warranty required by code, they provide a ten-year structural warranty and offer double warranty protection from 2-10 that ensures your warranty will always be covered.

Geographical area. The area they serve is the West Coast of the US and “select places elsewhere”.

Cost. $438,520.00 is the estimated total price for the C6 which has 3 bedrooms and is 1288 sq ft.

16. G-Pod Americas

These guys offer a futuristic pod home and homes made of shipping containers. They do shipping containers the right way, which is to insulation them on the outside. This is the way to not have condensation in your walls.

The pods are also built with building science principles in mind though they do use spray foam in the roof and floor which I’m not a big fan of for chemical offgassing reasons and for performance in the long run.

brands I Will Review Next:

Croft – Maine

Collective Carpentry – British Columbia, CA

Simple Homes – Denver

Those that Didn’t Make the List

Reasons why these didn’t make the list: Insufficient focus on building science. Evidence of poor building practices or lack of anything to demonstrate “above and beyond” mold prevention.

Flex house | Delivered complete. The house is made with FSC-certified lumber, low or no VOC materials, and low Global Warming Potential. BaySeal closed-cell insulation. I’m not a fan of spray foam. Their website is down in 2023.

IdeaBox | These are modular homes that don’t look different than mobile homes or your average tiny home. The photos of the build appear to show standard construction with saggy fiberglass insulation. (Not good if it’s saggy).

Greenfab | Some info on green building, but insufficient evidence on advanced building science and mold preventative building.

Blu Homes | Make nods to green building and mold reduction by using wood floors and by “building well” but with no actual evidence I can find of how they build differently; how they build well; what their walls, roof, floor systems are; and how they are mold preventative. They do use metal framing, which is especially tricky to manage condensation and thermal bridging in.

Clayton Homes | From what I can see from the video, it looks like an exterior vapor barrier, there is no rain screen, and the roof looks like it also has a plastic barrier. These look like typical mobile/manufactured homes.

Dvele | A new company, it sounds like they have display homes as of 2018 in California. They founded in 2016 after running a Canadian prefab company. They are Passive House certified. Use Rockwool on all 6 sides, they say. They use some possibly higher VOC materials inside like epoxy. They use moisture monitors in the walls. Insufficient information on the website to make a call on this. This company might be decent, but if they are building to high standards, they should make this more obvious.

Deltec | Looks really standard. They make wall panels. Tyvek, plywood, regular framing. Not sure how those panels come together, still have to finish the rest of the insulation and everything as usual. They have pictures of what looks like vented crawl spaces (that’s a no from me), and gutters coming off the side close to the house with no kick out (that’s a no for me). I don’t have a lot of confidence in these panels, or the installation, from what I have seen.

MADI Homes | This flat-pack house is beautiful and temptingly simple. But from what I could pull out of them in emails and from photos, it sounds like flash and batt insulation plus a poly interior vapor barrier (that’s a double vapor barrier). A no-no for me.

IT House | I liked the IT House initially, because of the large amount of glass used, and elevated off-the-ground designs. The structure is metal beams. The panels which are not load-bearing are made of cement board 3form resin panels, and solid wood thin paneling (I don’t really know what that means).

Finish panels are either fiberboard cement or 3Form eco-resin (for interior wet location). I’m still confused on how they build and what the panels look like. Reportedly, they have changed the system since then. That’s why I don’t like prototypes. They have not bothered to update the website.

Their display house is a bnb. A friend checked out the display house and wasn’t totally satisfied with the construction. The website says IT House is $150/sf but a client found it to be more like $400/sf in actuality.

The company had not updated the webpage or Instagram for a very long time. The website is now down in 2023.

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Concluding Thoughts

Look at the story of Greenterra Homes, a company on many green prefab lists just a couple years ago—the company went down epically.

My private notes on this company said “don’t see anything green about them—external foam on metal frame, with poly on the interior, double vapor barrier (no). Laminate flooring with OSB.”

They were clearly building cheaply. It turned out to be even worse than that.

Do not rush into a prefab purchase. As tempting as it can be with all the beautiful and affordable models, and the urgency of safe housing, you have to build this right.

Prefabs are not necessarily better or worse than custom houses. They can easily be worse than most, while many are better than what the average builder can produce. A really good prefab design has benefits, mainly being built out of the rain and with fewer mistakes.

If you need to build something less expensive and smaller see my post on small prefabs.

Corinne Segura is an InterNACHI-certified Healthy Homes Inspector with certifications in Building Biology, Healthier Materials and Sustainable Buildings, and more. She has 10 years of experience helping others create healthy homes. You can book a consult here.

This post took 30+ hours to research and write and is not sponsored or affiliated with any companies. If you found this post helpful, join the Substack to support the research behind this blog. Thank you!

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