Last Updated: Oct 16, 2021
As sustainable building methods continue to advance and gain popularity across the country, homeowners are finding that “green” building companies are moving toward greater specialization, which gives them more choices on the level of customization and the sustainability aspects of the home. Homeowners John and Barry live in one of these specialized homes in North Carolina: a prefabricated, panelized home that is net-zero ready, constructed by Deltec Homes. Founded in 1968, Deltec Homes, a family-owned Certified B Corporation based in Asheville, North Carolina, specializes in creating high-performance prefabricated net-zero energy homes—not your standard homebuilder.
John and Barry wound up choosing their new home from Deltec’s Renew Collection, which consists of three different home models—Balsam, Ridgeline, and Solar Farmhouse—that are “pre-designed to use two-thirds less energy than a typical home; the remaining one-third can be powered with renewable energy,” according to the website. They selected the Ridgeline, a model designed with a passive solar layout and for high-performance living.
The 1,765-square-feet home was strategically sited in a meadow to maximize solar exposure and allow for passive solar heating. “Since we moved into the home in February 2019,” John says, “we have realized great energy savings. The certification process has estimated that our annual energy savings will be $2,335. We have an all-electric home, and due to our 18 solar panels, we generated more power than we used in April and May and were not charged for any electricity usage during these months.”
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 which 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 LED lighting; water-saving fixtures; and energy-efficient appliances. The home has been certified as Zero Energy Ready, Indoor airPLUS, and an Energy Star home.
John and Barry were able to customize their model, to create more interior and outdoor space. “Our Ridgeline model is designed with two screened-in areas within the home proper,” they explain. “We modified our plan to wall in those areas to provide more interior living space. At the same time, because outdoor living space is important to us, we added a screened-in breezeway between the house and the garage, which provides an additional 192 square feet of three-season usability.”
“In addition, the sliding doors in the dining room made it easy to add an 800-square-foot outdoor patio from those doors to the garage,” the homeowners add. The amount of outdoor living area allows the couple to effectively increase the square footage of their home while enjoying greater access to the natural world through biophilic architectural design. Because the house is all one level, it’s perfect for aging-in-place—one of their primary concerns and sustainability.
“We like the open floor plan, the amount of natural light inside, the many green features, and the no-step accessibility throughout,” John says.
“Prefabricated,” “modular,” and “panelized” are often used interchangeably, but there are differences. According to the Deltec website, prefab refers to a home with sections of the structure built in a factory and then assembled on site. Modular and panelized are sub-types of prefabricated homes.
“Modular homes are built almost entirely in a factory,” the website explains. “The house is constructed in separate box-like modules—complete with attached walls, floor, ceiling, wiring, plumbing, and interior fixtures—which are transported and put together onsite.”
With a panelized building system, which is what Deltec offers, the “structural components of a home (walls, roof, and floor systems) are constructed in a factory and delivered to the job site where they’re assembled. Panelized houses must follow state and federal building code requirements and can be regularly inspected, just like site-built homes.”
Then, a panelized prefab home is a combination of a conventionally built customized wood-framed home and a factory-built home, which has significant parts of it pre-made, in addition to the standard components, including pre-installed siding and windows. This saves assembly time on the site, which means it can save you money.
One super-sustainable aspect of prefab homes—both modular and panelized systems—is that they drastically cut back on the material and construction waste associated with home construction. The EPA estimates that “548 million tons of C&D (construction and demolition) debris were generated in the United States, in 2015—more than twice the amount of generated municipal solid waste.” Prefab homes allow for a much quicker construction timeframe and can cut back on the overall cost.
Why did the homeowners choose a panelized prefab? “We were attracted to the concept of prefabrication, or in Deltec’s case, panelization, because of the speed and efficiency with which the home can be built in the factory, and then the speed with which the outer shell can be erected and roofed in, thus minimizing the exposure of the interior to adverse weather conditions,” John and Barry explain. “In addition, Deltec’s manufacturing facility is powered with renewable energy, and the company endeavors to minimize waste and recycle as many left-over building materials as possible.” They liked that Deltec considers the long-term impact of every aspect of the home, including where and how materials are made, how they’ll perform in terms of energy use, air quality, and durability.
In addition, independent third-party verification through a green building standard or program such as Energy Star, Green Built NC, or the Zero Energy Ready Home standard offers a critical quality assurance piece. While many home builders and architects might view building certification programs as an added constraint, Leigha Dickens, Deltec’s Green Building and Sustainability Manager, welcomes them. She explains, “The fact that the home is performance tested and inspected by a knowledgeable third party is a way to ensure better results than just trying to be sustainable without verification behind it.”
John and Barry wanted to maximize the sustainability and livability of their home. “We advise future homeowners to investigate companies and their model options,” they recommend. Deltec offers a building seminar several weekends each year, during which representatives explain the building process and provide home tours.
“We attended a seminar in 2016, then worked for several years with Deltec designers to determine the exact design,” they say. “During this process, we were able to maximize the sustainable and accessibility features we wanted for our home.”
After designing and building their home, the couple has found tremendous gratification in seeing the home’s verifiable positive impact on the environment. “Our phone apps, which enable us to check how much our solar panels are producing, tell us that in four months this system has saved approximately 4,744 pounds of carbon dioxide emissions and planted the equivalent of 119.49 trees,” John says. “That’s a good feeling.”
Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.