Plant Prefab 

The company, based in Rialto, CA, is the first custom modular and panelized home builder dedicated to sustainable building, materials, processes, and operations to achieve B Corporation certification. "As a socially responsible business, we've always been committed to wedding purpose and profit in our work," said Steve Glenn, founder, and CEO, in a press release.

They went on to say that they used the US Green Building Council's (USGBCs) LEED program for many years to secure third-party verification of their sustainability and performance. They consider B Lab to be an equivalent authority to measure the company's impact. They have an extremely comprehensive process and require that companies undergo verification every three years to maintain compliance.

Deltec

Well-known for its round-house prefabs, Deltec works with clients to achieve the level of sustainability they're seeking. Whether homeowners are simply seeking energy efficiency or aspiring to net-zero, the company designs homes that seamlessly connect the indoors and outdoor landscape. The prefabs are fabricated in a factory powered by 100% renewable energy. Based in Asheville, NC, the company also has a recycle and reuse program that diverts more than 80% of waste away from landfills.

Ahead of the curve, Deltec won a US Department of Energy's DOE Housing Innovation Award in 2019. We featured one of Deltec's non-circular, net-zero panelized homes from the Renew Collection, which uses two-thirds less energy than a non-sustainable home. The homeowners upped the ante by powering their all-electric home with 18 solar panels.

Phoenix Haus 

We recently found out about Phoenix Haus, which has its own plant in Grand Junction, CO, where the company fabricates its net-zero, Passive House prefabs. That's quite a combination—and it works. On your next trip to the Rockies, you can experience one of the projects, H19, which is now on Airbnb.

After working through numerous iterations, Phoenix Haus came up with Passive House design and construction underscored by its certified Alpha building system. H19's super-insulated roof and wall panels, triple-pane doors and windows, heat pump, and 12 solar panels powering the electric house are quite the winning combination.

Bamboo Living

Based in Pahoa, HI, this fascinating prefab company creates the "only internationally certified, permit-ready bamboo homes and buildings in the world," according to Bamboo Living's website. Durable, low-maintenance, pest- and insect-resistant, and able to withstand hurricanes with winds more than 200 mph, these prefabs are built for resilience.

The sustainability key here is bamboo, which the company uses in its prefab construction instead of wood. Bamboo is a fast-growing natural material and provides options for building practices that save forests and natural resources. Bamboo, the company says, is a renewable resource that requires less energy and creates less pollution and waste. The tiny-home model, delightfully named Bonsai, is an excellent option for off-grid living.  

FabCab 

The architecture firm behind FabCab's stellar sustainable homes offers two "timber cabin" style prefab homes: TimberCab and ModCab. Both have broad expanses of glass that bring the outdoors inside and high ceilings made possible by modern shed or gable roof designs. Wood's the thing in these prefabs. The homes utilize exposed Douglas Fir timber framing and SIP panel construction.

Based in Seattle, WA, FabCab incorporates universal design principles into its prefabs for gracious living as homeowners age in place. The home packages are sold as a kit of precision-cut and labeled parts. These can be purchased as parts only or as complete homes, including assembly, finishes, foundation, site work, and permits. Interior features options include bamboo and recycled carpet flooring, in-floor hydronic heating, and energy-efficient appliances.

EcoCraft 

The models offered by this Pittsburgh, PA, company are all Passive House certified. This means that the prefabs are built to PHIUS specifications that include an airtight building envelope, high-performance windows and doors, and thermal bridge free construction. ERVs provide continuous, fresh, filtered air for a healthy home. The team has also selected building materials that are healthy, recyclable, and free of toxic chemicals and other contaminants.

The homes are also ENERGY STAR compliant. Models range from a traditional four-square style to modern takes on the classic mid-century ranch, chalet, one-level universal living, the farmhouse, and Craftsman style.

Dvele 

Yes, modern luxury is possible with Dvele, which has its own factory in southern California for production for West Coast customers. With four customizable "mini" prefab homes (perfect for ADUs), and nine other customizable prefab templates ranging from a cottage-sized version at 888 square feet to multi-level homes at more than 3,000 square feet, all options are sustainable. 

The company sources sustainable materials and works with partners who do the same. These Passive House certified homes are constructed and insulated to be airtight and energy-efficient. Solar is always an option to take the house to net positive. The electric homes also include high-efficiency hot-water heaters and induction stoves. Dvele also, for each dwelling it finishes, plants 10,000 trees. 

Shelter Dynamics 

This California company innovated the Flex House, a small footprint, energy-efficient, factory-built smart house that’s cost-effective, healthy, sustainable, and delightful to inhabit. Designed by modular housing pioneer Jim Gregory, the Flex House includes:

• A 2.5 kW solar array (with optional upgrades, battery backup, and full off-the-grid capability)
• All-LED lighting with smart home automation control
• A mini-split heat pump HVAC system
• Double-glazed windows, and 
• R-40 insulation in the floor and ceiling and R-30 insulation in the walls. 

Honomobo 

Honomobo's prefab shipping-container homes are factory-built using rigid steel. They feature floor-to-ceiling windows and a sleek, minimalist style that integrates indoor and outdoor living. The H Series ranges from a plug-and-play home office or studio to a four-bedroom, three-bath, 1920-square-foot home comprised of 6 x 40' shipping containers and large glass walls. The California company also can outfit the homes with solar arrays to make them net-positive. 

GO Logic 

The Maine company has a portfolio of sleek contemporary designs that range from a 600-square-foot single-bedroom cottage to a 2,500-square-foot, four-bedroom family home. All GO Logic designs are optimized for comfortable open-plan living, low operating costs, and durability. The super-insulated, air-sealed building shells on these prefabs have been designed to use 80% less energy than a conventional new house. An efficient energy-recovery ventilation system delivers a continuous supply of fresh, tempered outdoor air to every room in the home. If the site has good solar exposure, the company can add a photovoltaic array for a zero-energy home.