Maxed-out townhouse lays the groundwork for minimal impact on the environment

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Numerous individual architects and private builders have contributed to innovations in sustainable home building by designing self-powered modular homes and residences, but few of those known as “production” builders have taken this step.

Production builders include local, regional and national home builders who design and build multiple homes at once, rather than a personalized home for a single buyer. But to move the sustainability needle for the future, builders of all types will eventually need to design and build homes with environmental concerns among their top priorities.

“It’s more common for single-family home builders, particularly private builders, to build modular homes on the West Coast than on the East Coast because there are more factories in the West,” says Cindy Wasser, senior director of green building programs for the home. Upper Marlboro, Md.

“On the other hand, production home builders have more consistent teams of contractors working in their homes and can benefit from modular construction.”

Modular home construction addresses environmental concerns, speeds up construction, and can start to make a dent in the severe home shortage in the United States. Freddie Mac estimates that by the fourth quarter of 2020, approximately 4 million residential units are needed to meet demand.

“Modular construction helps reduce variables in a home’s components, which helps construction crews reach their goals faster,” says Wasser. “Building parts of homes in a factory controls waste, allows for more recycling and reduces time spent on site for workers.”

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Van Meter Homes, a northern Virginia-based regional home builder, has recently completed its second “POWERhaus,” a modularly built townhouse in Chantilly, Va., which the company uses as a prototype for its future townhouse development. Its first prototype was a single-family home.

“We have a factory in Winchester, Virginia where we have been manufacturing roof trusses and wall trusses since 2008, so we wanted to do more in a factory setting for greater efficiency,” he says. Mike Sandkuhler, vice president of building operations at Ashburn, Va-based Van Meter Homes, said: “Also, most people in the construction industry know that the skilled labor shortage we experience has not gone away. The modular structure can help us manage this shortfall.”

Sandkuhler says Van Meter plans to add more townhouses to its product mix in the future, so the company has chosen to design a modular townhouse for its second project.

Van Meter Houses were brought Joseph Wheeler, professor of architecture and co-director of the Center for Design Studies at Virginia Tech’s School of Architecture + Design in Blacksburg, Va., was a consultant while on a research leave to help redesign a model of a townhouse as a prefab concept.

“The focus was on developing cartridges that could be manufactured in their factories for greater efficiency,” Wheeler says. “Cityhouses require a firewall between each unit, so we had to do research and development to be able to do this in a modular factory setting.”

Two month construction period

A big advantage of this modular construction is that the townhouse was built in two months, which most new builds take much longer.

“The beauty of modular construction is that you can work on site preparation and foundation at the same time with factory-made cartridges,” Sandkuhler says. “It cuts down the construction time from four or five months to two months.”

Van Meter and Wheeler take the lessons they learned while building this townhouse for their next project for their four-row row house in Ashburn. Sandkuhler predicts these summer homes will be in place this summer.

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“The factory is less than 45 miles from where we built it, so we reduce the amount of fossil fuel and the time it takes to transport cartridges to the job site,” Sandkuhler says.

According to a 2019 PBS News report, transportation and housing account for more than half of all greenhouse gas emissions in the United States, with 33.6 percent of these emissions coming from housing. Utility use accounts for 25 percent of residential emissions.

Wheeler says reducing the distance from the factory to the home site also solves the problem of trucker shortages.

“We also learned that it’s better to make smaller-scale modular parts rather than large panels, because that way you don’t need large cranes and huge trucks that can be difficult to maneuver in residential areas,” Wheeler says. “Smaller components are also more flexible in terms of design, so you don’t get stuck with that big box mentality of previous modular homes.”

Future-proof Chantilly mansion

The first POWERhaus townhouse model listed for sale at $899,990 includes 2,706 square feet of living space with three bedrooms, three bathrooms and a two-car garage. The model includes several features as it serves as a research project for Van Meter.

In addition to solar panels, Tesla home batteries to store power, and an electric vehicle charging station, the home has high-tech features such as a self-cleaning bathroom, a whole-home security monitoring system, smart mirrors, smart lights, and contactless faucets.

The “power” part of the name represents the goals of the townhouse, including:

  • Progressive for innovative construction techniques.
  • It is optimized to provide the highest performance for all systems in the home.
  • To create processes that minimize waste with waste awareness.
  • Efficient, to maximize energy efficiency and comfort.
  • To increase sustainability by using renewable and clean energy sources.

“We choose one of our most popular floor plans available to turn it into a modular design for this home,” Sandkuhler says. “If you walk into this house, it doesn’t feel like a modular home.”

Wheeler says Van Meter uses optimization software that keeps track of every piece of material used in the factory and where and when it’s needed, which could reduce the costs of future modular built homes.

“For the next townhouse set, we can build a car like a Lego nesting products set with all the pieces in it,” Wheeler says. “There is less waste and lower costs when we can build more efficiently and more precisely.”

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Wheeler says they quickly learned it was best to leave the roof of the upper two floors open to make it easier to put everything in place when shipping the cartridges.

“In the future, small-scale modular homes will offer homeowners and builders the ability to scale over time,” Wheeler says. “If you design a community from the start that will be modular, you can develop the spaces and spaces between the houses to accommodate the addition of future modules. So for the price you can start with a two-bedroom, one-bathroom home and expand to a four-bedroom, four-bathroom home.”

Ultra energy efficient homes

While Van Meter’s next batch of modular townhouses will be energy efficient, Chantilly POWERhaus is meeting net positive standards, meaning that the house produces more energy than it uses. The combination of solar panels, airtight construction and extra insulation along with the Tesla Powerwall to store solar energy means there should be enough extra energy to charge an electric car and power the home.

“The determination to design and build net positive homes is the direction the market is headed, but the latest innovations are often found in the designer luxury home market,” says Wasser. “Builders and consumers are really realizing the need for more sustainable energy, lower energy bills and homes that can withstand power cuts.”

Established in 1995 and developed by the nonprofit Residential Energy Services Network (RESNET), the Home Energy Rating System (HERS) measures energy efficiency in homes. The lower the HERS number, the more energy efficient the house. A HERS score of 100 means a home was built to 2006 energy efficiency standards. A typical resale home has a HERS score of 130. A HERS score of zero means the house produces as much energy as it uses. A net positive house has a negative HERS score.

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“This is an all-electric house and it provides a higher level of energy efficiency, not only because of the way it is built, but also because of the systems we install,” Sandkuhler says. “It has induction cooking and a highly efficient, ductless, multi-zone mini-split heating and air conditioning system.”

Wheeler says the Mitsubishi Multi-Zone Mini-Split system is compact and allows you to heat or cool one floor of the house at the same time, instead of the whole house. The townhouse also has motion sensors to control the lights and a whole-house energy monitoring system with leak detectors that automatically shut off the water in case of a leak, all contributing to the sustainability of the home.

“In a townhouse you get a slight energy efficiency advantage over a single-family home, especially the indoor units, because of the insulation benefits of combining the houses,” says Wasser.

Not the ‘cheapest of the cheapest housing’

Sandkuhler says that building cartridges for a house in a factory provides a controlled environment that eliminates air delays, but the process has yet to save money.

“We’re saving time in the field, but so far the costs haven’t dropped,” Sandkuhler says. “Our first goal in this project was for research and development and our second goal was to increase efficiency to make it as comparable as possible to houses built on-site.”

Building four kitchens at once is efficient, but Sandkuhler says the attention to every detail is the same as onsite construction.

“Stacking cartridges requires a different level of precision,” he says. “You have to coordinate every detail. For example, we want all of our homes to be solar ready in the future, but that means we need to modify the roof trusses so they can handle the additional weight.”

Increasing the affordability of homes built with modular construction is another challenge.

“The goal isn’t to build the cheapest home,” Wheeler says. “The goal is to deliver an excellent quality product more efficiently. Eliminating waste and exposure to weather can reduce costs and thus tailor the use of labor in the factory.”

Eventually, Wheeler believes, more skilled contractors will do some of their work at the factory.

“If all the components of each house are uniform and precise, the on-site part of the construction can be done more easily and you don’t need a supervisor to oversee everything,” Wheeler says.

A misconception many consumers have is that a modular built home will be more difficult to renovate or remodel in the future, Wasser says.

“In fact, components made in a factory have huge benefits for consumers,” says Wasser. “A more controlled environment for build that allows for higher quality ingredients and greater consistency. It does not affect the modifications at all. Homeowners will be able to do whatever they want, as if the house was built on site.”

Builders can also “future-proof” a modular home if they wish, such as laying cables for a battery panel to store solar energy.

“Consumers can come into a showroom and make choices, just like with any other type of new construction,” Wheeler says. “The biggest difference is that they can be moved home in two months instead of two or three times longer.”

For Wheeler and Sandkuhler, investing time and money in research to build the POWERhaus is about using technology to build a better home that will give homeowners the same experience as any solidly built home built using traditional methods.

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