How green can a house get?

Here are two answers, one in Saint Paul and one in Minneapolis. Intended as livable experiments in radical sustainability, both houses were designed as demonstration projects of a sort, to innovatively synthesize green products and technologies with the best in residential design while harnessing the sun's energy. The names the homes were given--EcoDEEP Haus and ICON Solar House--have become brands that tell a story of sustainability.

Going Deep

EcoDEEP Haus is the name of the 1940s bungalow that architects Kevin Flynn and Roxanne Nelson transformed into a modern, livable model of sustainable design. (EcoDEEP is also the name of Flynn's St. Paul-based architectural firm.) While the couple doubled the size of the home to meet the needs of their growing family and urban lifestyle, they reduced the house's energy consumption by 40 percent. Accolades quickly followed the house's completion in 2009.

In addition to winning a 2009 Evergreen Award, AIA Minnesota and Mpls.St.Paul magazine honored EcoDEEP Haus with a Residential Architects Vision and Excellence Award, and the Minneapolis Star Tribune included it as a 2009�10 Home of the Month. Discovery's Planet Green network aired the house on its "World's Greenest Homes" program last fall.

"We did a lot of cool stuff," Flynn says of the sustainable technology incorporated into the 1,700-square-foot Cape Cod in St. Paul's Highland Park neighborhood, which the couple transformed into a high-performance, energy-efficient, 3,200-square-foot modern home.

That "stuff" includes rooftop solar panels that provide both electricity and hot water. A 1.44-kW photovoltaic system, consisting of eight 3-foot-by-5-foot panels, generates about 30 percent of the home's total electricity supply. Two 4-foot-by-8-foot solar hot-water panels heat water in a 90-gallon thermal storage tank; depending on the season, the system supplies 100 to 50 percent of the family's hot water.

Half of the house's roof is covered with a 4-inch-deep mat of vegetation growing from a LiveRoof modular-tray system. The other half is covered with a white reflective-cooling membrane. Flynn and Nelson clad the house's exterior in FSC-certified fiber-cement-board siding, and corrugated metal siding.

Sexy and Unsexy Features

Inside, the couple outfitted the house with energy-efficient fixtures and appliances, including a 92-percent-efficient furnace and 86-percent-efficient gas water heater. Low-flow fixtures and dual-flush toilets reduce water use by 64 percent compared to other houses with similar square footage. Sustainable finishes include low- or no-VOC paints and adhesives, recycled-glass terrazzo and recycled-paper counter tops, and salvaged oak flooring.

All of which "gets a lot of attention," Flynn says. "But I remain steadfast in my belief that the absolutely best thing one can do is first reduce a building's energy load by incorporating very unsexy things like good insulation and air sealing, and making the right window selection, to get a good thermal envelope. Also, designing the house to utilize passive energy and passive ventilation is pretty key."

Cell spray foam and blown fiberglass insulation contribute an R-value of 60 in the roof cavity, while the rim joists and walls are insulated to R24. The architects' strategic window placement allows natural light into the house, and promotes passive heating in winter and cooling in summer. Fluorescent and LED light fixtures keep energy use to a minimum.

EcoDEEP Haus, Flynn says, "is an embodiment of my values and practice. It demonstrates my commitment and passion for this type of work. A lot of people drive by and check out the house; some even stop and say hello and talk about how much they like it, which is nice. I'm currently working on a couple of passive houses and looking at creating living buildings, so I'm really excited about the growth of interest in this direction."

An ICON of Sustainability

The other super-sustainable project, ICON Solar House, was designed and built by a team of students and faculty from the University of Minnesota's Institute of Technology (now the College of Science and Technology), College of Design (architecture, graphic design and interior design), and College of Continuing Education. The interdisciplinary team was one of 20 university-led groups invited from throughout the United States, Canada, and Germany to participate in the U.S. Department of Energy's fourth annual Solar Decathlon. The team's mission was to design, build and operate a livable, energy-efficient and aesthetically appealing 700- to 800-square-foot house--powered only by the sun.

Inaugurated in 2002, the Solar Decathlon's goals include educating participants about energy efficiency, renewable energy and green building techniques as they design and construct the houses. Team members collaborate across disciplines to generate integrated approaches to the design and construction of solar-powered homes. More than 150 U of M graduate and undergraduate students, with the guidance of their professors, worked on the ICON House.

Competition was fierce. The gable-roofed ICON house took fifth place out of 20 teams. But the U of M beat out world-renowned German engineering to win "top entry" in the lighting design and engineering categories. The team also took third in appliances and home entertainment. The house currently sits next to Rapson Hall on the U of M campus. Open to visitors, the ICON house is for sale.

Solar Here, Solar There

The building's gable roof mimics the vernacular simplicity of traditional Midwest homes. In keeping with that theme, the 800-square-foot ICON house has a pine framing system featuring a 12" wall with a staggered stud and blown-in insulation. The house is clad in rain screen of composite material with a dark-wood stain.

The multiple solar technologies incorporated into the house include BIPV glass (with integrated photovoltaics) on the sun porch and south windows; and SageGlass® in the kitchen, which has embedded argon gas that darkens in sunlight to adjustable comfort levels. Photovoltaics from BP Solar are on the roof and provide most of the energy.

Viessmann solar-thermal systems on the roof and south wall power a desiccant-dehumidification system the team innovated. The system heats hot water to regenerate the liquid desiccant solution, which is about 35 percent more efficient then using electricity in the dehumidifying process. Such ingenuity addresses another of Solar Decathlon's goals: research and development of new solar technologies.

Designed and constructed in Minneapolis, the ICON House had to be disassembled and reassembled on a site within the Decathlon's "solar village" on the National Mall in Washington, D.C. for the competition. Teams--and their houses--competed in 10 contests that evaluated the house's architecture, engineering, lighting design, and market viability. The contests also tested how well each house's solar technologies maintained hot-water temperature, ran appliances and electronics, and maintained a comfortable air temperature of 72 to 76 degrees, with a relative humidity of 40 to 55 percent.

Now back home on the U of M campus, the ICON House offers visitors a chance to relax in the sun, while examining a variety of solar technologies at work. According to Ann Johnson, who wrote the proposal and was the team's project manager, the ICON House offered students an opportunity to research and develop an interdisciplinary housing project, and experience the rewards of their labors.

Whether they're using existing sustainable technologies or innovating new green systems, faculty intent on practicing what they teach and architects seeking to practice what they preach are powering their dream houses with the sun.

Camille LeFevre's last article for The Line was a report on the University of Minnesota's new product design program, in our October 13, 2009 issue.


Photos, top to bottom:

EcoDEEP Haus, in Saint Paul's Highland Park

an EcoDEEP hallway

The clean lines of EcoDEEP's kitchen

(photos courtesy EcoDEEP Architects)

The ICON Solar House soaks up winter sun.

Eating area and...

...living room in the ICON

(exterior shot by Bill Kelley; other photos courtesy ICON Solar House Project)