Our Top 5 Sustainable Prefabs in 2019

Rise readers (and writers) love them. Design magazines drool over them. Celebrities, especially those into environmental activism, are intrigued. The technology to create them continues to innovate faster, simpler solutions to fabrication. We're talking, of course, about prefabs, or prefabricated homes. More specifically, sustainable prefabs, in styles from cottagey and colonial to boxy and modern, and from tiny to significant square footage.

Prefabrication is how every home should be built now and into the future, claims Sheri Koones, author of Prefabulous Small Houses and Prefabulous + Sustainable: Building and Customizing an Affordable, Energy-Efficient Home. Still, prefab homes made up just two percent of new single-family houses in 2016, according to the U.S. Census Bureau. We're hoping this list of five fabulous prefabs, our favorites of 2019 thus far, can help remedy that situation.

Our prefab faves have a lot in common. First, they can cost less than a traditionally built home (depending on customization). Second, they save time: typically, a prefab takes 50 percent or less time to construct than a traditional home, which translates into financial savings on labor. Third, components and panels are fabricated in a climate-controlled factory, delivered to the site, and assembled on-site—limiting construction waste. And finally, sustainable strategies, from solar arrays to low-VOC finishes, are incorporated. Some are even customizable to net-zero, net-positive, or off-grid. Let's take a look.

1. Cocoon9: Micro Home

New York-based Cocoon9, a designer and manufacturer of prefab dwellings, has created a collection of micro homes. The company describes them as "plug-and-play houses with the sophisticated features of a custom home or luxe resort." Cocoon9 has introduced three-floor plans: The Cocoon Cabin (a one-bedroom prefab); and the Cocoon Studio and Cocoon Lite 20, which both have open-plan layouts.

Think Swiss knife with Cocoon9's prefabs: The furniture, appliances, and storage areas open up and fold away into walls, floors, and ceilings to maximize space. As for sustainability, the models incorporate such sustainable materials as F.S.C. certified bamboo and insulated glass with thermally broken aluminum frames. (The term "thermally broken" refers to the window's construction: The aluminum frame window is fabricated with a barrier in between the inside and outside window frames, which prevents the thermal energy loss.) All of the models are also equipped to accommodate solar panels and roof gardens.

2. Deltec: Renew Collection 

Deltec has been designing and constructing prefabs across the U.S. since the late 1960s. Currently, the Asheville, NC, company is being recognized for its energy-efficient prefab models. It's also a certified B Corporation. Deltec’s new Renew Collection is getting a lot of buzz. The models are prefabricated, panelized homes with a passive solar layout that can be net-zero ready. Homebuyers receive energy modeling based on the weather in the homeowner's region, and the company will customize the construction based on-site, climate, and homeowner needs. The Renew prefabs are certified as Zero Energy Ready, Indoor airPLUS, and as ENERGY STAR homes.

Other sustainability features include 2x6 exterior walls with advanced insulation; Marvin Integrity windows; a Mitsubishi electric combination ductless and ducted hyper-heat mini-split heat pump; a heat pump water heater; a recirculating hot water system that supplies hot water on demand to the bathrooms without needing to "run the water" until it is hot; interior paint with zero volatile organic compounds; all L.E.D. lighting; water-saving fixtures; and energy-efficient appliances.

3. Stillwater Dwellings

Stillwater Dwellings, based in Seattle, offers large prefab panelized homes in more than 20 models. The LEED-accredited designers can also customize a model to a buyer's specifications. Stillwater prefabs are particularly popular in areas with wildfire, as the company specializes in fire-resistant housing as well with "Fast-Track" plans to get a family back into a home quickly after a fire.

For this company, "Energy efficiency and sustainability are at the heart of our design philosophy," according to the website. Stillwater Dwellings' fabrication system utilizes prefabricated panels produced from high-quality, manufactured timber. The company says the timber "is superior to solid, sawn timber from which traditional homes are built." In this way, the construction process doesn't rely on wood from old-growth forests and uses 50 percent fewer materials compared to traditional building methods.

The prefabs are also highly insulated and tightly sealed to reduce energy costs and environmental impacts. Exterior walls are rated at R28 and roofs at R50. Low-VOC paint is used throughout the homes, and kitchen and bathroom countertops are made from recycled glass and porcelain. The homes also come ready to accommodate photovoltaics and electric car chargers.

4. P.A.T.H. by Starck with Riko

Also across the pond, French architect Philippe Starck, in collaboration with the Slovenian building company Riko, has innovated a Prefabricated Accessible Technological Homes (P.A.T.H.). A P.A.T.H. prefab uses an FSC certified wood-frame exterior; the interior walls are filled with cellulose thermal insulation around floor-to-ceiling glass windows and doors. The all-wood shell allows clients to maximize energy efficiency and insulation. The framing thickness and insulation can be adapted to fit even the most stringent Passive House standards.

P.A.T.H. utilizes renewable energy sources for heating, cooling, and ventilation. P.A.T.H. homes come renewable-energy ready to install solar panels, heat pumps, wind turbines, rainwater collector systems, and other essential elements of sustainable design. Clients can opt for packages that turn the P.A.T.H. home into a zero-energy or even positive-energy home.

As Starck told Rise, "Building your own house can be extremely risky: we know when it starts, but not necessarily when it ends, or how much it will cost. With P.A.T.H. and thanks to the industrial production of prefabricated components, in six months and for a defined budget, anyone can access a home." 

5. Alchemy Architects: weeHouse

In 2003, Geoff Warner, founder of Alchemy Architects in St. Paul, Minnesota, started with a seemingly simple idea: To design a sustainable prefab home that clients could buy in an easy, off-the-shelf way. After the first award-winning weeHouse in Wisconsin was built, things didn't go as planned. "With the weeHouse, we originally thought clients would choose a plan, and we could execute it with a factory partner in about three months," Warner says. "It didn't work that way. The weeHouse modules we showed were just starting points for customized homes." 

Those clients' desires to mess with the model, however, have driven Warner and his team to become more innovative, flexible, and adaptable with the original concept. In addition to customized weeHouses, the team has created the lightHotel art project, a tiny sustainable motel room, and "beacon for ecotourism and sustainable living," on wheels that moved around Minneapolis and St. Paul—including two museums, a community garden, and a city park.

In turn, the lightHotel informed the development of lightHouse, a low-energy A.D.U (accessory dwelling unit) currently under construction in Sebastopol, California. A lightHouse can be stick-built or constructed in a factory and delivered as a module or S.I.P.s kit-of-parts, depending on on-site access. (SIPs are structural insulated panels.) The Sebastopol lightHouse is being built out of 2x4s, with R50 12-inch neo-core S.I.P. insulated panels, and a plywood wall interior. The lightHouse also has passive house windows that are triple pane and tilt-turn, as well as insulated sliding doors. Roof insulation and white roofing, per California code, are also part of the construction.

Over the years, and in collaboration with various clients, Alchemy has kept customizing the prefab weeHouse, with iterations that include decks, stairs, garages, upper and lower levels using stacked modules, cantilevered modules, and "skyway" or underground connections between modules. They've planned weeCommunities and weeHouse family compounds. They've also designed a weeHouseBoat. "Wee" get excited about every new project.

As the prefab housing market continues to evolve, we can't wait to see what's next! Know of other stellar prefabs? Let us know!

Article by:

Camille LeFevre

Camille LeFevre is an architecture and design writer based in the Twin Cities.