The Anatomy of Innovation

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While large national and regional builders might have the resources to be leaders in innovation, small builders with a clear sense of purpose also can be effective early adopters of technology.

June 01, 2003

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"To start a journey of a thousand miles takes but one step." It's a favorite quotation of John Wesley Miller, who took his first step on the road toward innovative building 30 years ago. Now Miller can count the developmentof Armory Park del Sol among the notable milestones of that journey. A sustainable community in the historic inner city of Tucson, Ariz., its grid-connected homes feature solar energy technologies, thermal mass construction and many other energy- and resource-efficient technologies.

Innovative builders come in many different packages. While large national and regional builders might have the resources to be leaders in innovation, small builders with a clear sense of purpose also can be effective early adopters of technology. And Miller might be one of our strongest examples.

His homes tell the story best. A typical Armory Park del Sol home has a 1-kilowatt photovoltaic (PV) system composed of eight to 12 PV panels on the roof of the garage. Miller has learned that the secret to success with solar is control, which he gains with thermal mass construction. The foundation slab is a minimum of 10 inches thick - 6 inches more than standard. Masonry walls are insulated on the outside with polyisocyanurate, an R-12 exterior foam insulation with three-coat stucco cladding. Conditioned air is stored in the thermal mass of the walls at night and released during the day when needed most. In effect, the walls and floor become part of the home's heating and cooling system.

A solar water heater, looking a bit like a skylight, sits on the roof of the house facing south, as close as Miller can get it to a backup on-demand tankless water heater. Thanks to more than six months of PATH-funded data collection conducted by the NAHB Research Center in one of his Armory Park homes, he discovered that a tankless water heater in collaboration with the solar water heater uses only half the energy of a tank water heater in the same environment.

The entire infill project creates a picture of minimal environmental impact. Homes are designed to meet strict energy-efficiency requirements, with a raised heel truss and high levels of ceiling insulation (at least R-38, with 14 inches of fiberglass blown in), ducts inside conditioned space, and low-E windows to minimize heat loss and gain. Energy-efficient equipment is standard (7.5 HSPF, 12 SEER). Ductwork was engineered for a balanced flow, and Aztec Air performed air balancing to improve performance and occupant comfort.

Each home is being equipped with the latest water-saving technologies, including an Energy Star-qualified dishwasher, range and microwave, and a dual-flush-system toilet. Xeriscaping adds to water conservation.

The net result? Homes that use roughly 50% less energy than average area homes. Miller's homes range from 1,100 to 2,400 square feet, at an average cost of $160 per square foot, and use about $1 a day for heating and cooling — all electric. Homeowners can look forward to a three- to seven-year payback on the solar hot-water system, along with a $1,000 Arizona tax credit. While payback on the PV system is in the 20- to 30-year range, Miller finds this doesn't limit the homes' appeal. Rather than focusing on the upfront cost, his buyers are groundbreakers: educated on environmental issues and eager to align their lifestyle with their values. And it doesn't hurt that their investment increases in value every time heating and cooling rates rise.

Sun Worshipper

Photovoltaic panels on the rooftops in Armory Park del Sol soak up the Arizona sun. The house on the right is the Zero Energy Home.

The crown jewel of Armory Park del Sol is the Zero Energy Home (ZEH). Funded by the U.S. Department of Energy to introduce the zero-energy concept into the mainstream home building market, the ZEH gave Miller a chance to build on his PATH-funded work and find out exactly what he could accomplish.

A zero-energy home is designed to produce as much energy as it consumes, resulting in a net zero-energy bill over a year. Just like a typical home, the ZEH is connected to the utility grid, but at times it supplies energy back to the grid. The DOE, through the National Renewable Energy Laboratory, funded the engineering development of the home as part of its Zero Energy Buildings program.

The finished home, with just more than 1,700 square feet of living area, is powered by a 3.5-kilowatt PV system with 28 panels, plus four more panels for a solar hot water and space-heating system with a 220-gallon tank. Through the Sunshare program of Tucson Electric Power, the homeowner's bill is guaranteed to come in at one-third of a typical heating and cooling bill, but the ZEH is expected to equal its consumption at year's end, for a net zero-energy cost.

Loaded with upgrades and premium landscaping, the ZEH is priced at $380,000, but Miller says he could build a basic net zero-energy home for $314,000.

The Challenges

The best friend of the solar-powered homes of Armory Park also has been the biggest enemy: The Tucson climate, with its ample sunshine, packs a large cooling load. Miller and his team conquered that by reducing the solar gains through large window overhangs, low solar heat gain coefficient windows, a reflective roof coating, and high R-values in the exterior and ceilings.

Integrating the mechanical system into the ZEH, while feasible on paper, turned into a bigger challenge than expected. The mechanical closet, located in a second bath, holds the 220-gallon storage tank, the tankless water heater, a washer and dryer, and an air handler for the air conditioner and heat. If he had it to do over, Miller says he would put it in the garage.

He takes the kinks in stride. "Every family home I've built has taught me lessons," he says. Along the way, he has learned what his customers want, what they're willing to pay for, the importance of quality control and the importance of maintaining good relationships with old customers who can refer new business.

Pride and Profit

A work of art. A passion. A chance to do the grand painting.

When I talked with Miller, this is the kind of language he used to describe what drove him to the Armory Park project. "To put all these ideas together in one place, in a good scale development of 99 homes — in the inner city — and to be part of the redevelopment of my hometown, doing quality-of-life building ..." The sentence hangs there, but the point is clear. He's jazzed.

For small builders especially, Miller believes, building with solar is an opportunity to do something good for the environment while also turning a profit. The developer/environmentalist divide bothers him. "We builders are environmentalists," he insists. "We're concerned with how we develop land, how we build the house. By utilizing renewable resources, such as solar, we emphasize the fact that we are environmentalists, that we care about the world we live in and that we're providing a better quality of life for the citizenry of our country."

But that's hardly the end of the story. Miller has shown there's money to be made in quality green building. He spent a year studying solar, soaking up everything he could, before he began to build. When he completed his first solar house in the mid-1970s, it sold immediately. Green building has been lucrative for him ever since.

"In most markets, an average builder could create a demand for solar by building one model home," Miller says. He advises offering a home with solar technologies as standard, rather than optional. "People just need to see it, feel it and become comfortable with the technology. A lot of people are afraid it's too complex. The job is to make it comfortable." After solid study and one year's work, he estimates a builder could profitably make solar home building 10% of the business.

Miller equates the risk involved in jumping into solar as equivalent to that in any spec building project. Most important in making the leap, he says, is believing in what you're doing.

Miller's journey of a thousand miles isn't over. He's turning away custom building opportunities to focus his attention on the Armory Park project, which he figures will take two more years, but he doesn't mind.

And then what? He has been wondering about how to make photovoltaics an integral part of the roof or house structure. That just might be next.

To read more about the technologies used in the Zero Energy House, please see

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