As a heart surgeon, Dr. Richard Mushorn has a special affinity for valves, which may explain his interest in irrigation.
Back in 2007, when he was looking toward retirement, Mushorn and his wife Lynn decided to build a new home for themselves. Longtime Phoenix-area residents and desert-lovers, the couple purchased a plot in a North Scottsdale subdivision known for custom homes amid natural settings.
Because of their affection for the Sonoran environment, the Mushorns developed some specific criteria for their future home: They wanted it to conserve energy, use solar power, harvest rainwater, and preserve as much of the native vegetation as possible.
Not sure where to find a contractor who would be up to the job, the Mushorns attended a Green Building Expo, where they met Doug and Kevin Edwards, brothers and co-owners of Edwards Design Group, an architecture and construction firm.
It was a serendipitous connection.
Kevin Edwards, who hosted Scottsdale's Green Building lecture series for 18 years, has been passionate about environmentally-friendly design since he was in high school. To him, the Mushorns were ideal clients.
"We hit it off right away," Edwards remembered. "They very much felt that doing something sustainable was important."
In turn, the Mushorns were attracted to Doug and Kevin's design aesthetic, particularly their use of natural materials like rammed earth.
"I like rammed earth because it's sustainable but also I just like the way it looks, kind of like sedimentary rock," Richard Mushorn said. "So I wanted to see what they could do with it."
What they did met all the Mushorns' criteria — and then some.
Completed in 2010, the home includes 4,600 square feet in a single story. The front entrance features two-foot-thick walls of rammed earth, which is created by mixing soil with concrete and pounding it into forms layer by layer.
However, the majority of the walls are constructed out of aerated concrete, which is lightweight, strong, and an extremely good insulator. Other exterior elements, including the roof, are made of self-weathering steel, which blends with the desert surroundings and requires no paint or maintenance.
A butterfly roof over the main part of the house creates wings that channel rainwater into the center, from where it flows into two 1,500-gallon storage tanks. Once the above-ground tanks are full, the excess is directed to an underground cistern that holds an additional 5,000 gallons.
"We originally estimated they'd be able to fill all the tanks twice a year," Edwards said, "but it's turned out to be four times a year."
The stored rainwater is used for the vegetable and herb gardens, and it was during the installation of the irrigation system that Edwards discovered Mushorn's aptitude with valves and hoses.
"I've never worked with a client so interested in how it all went together," Edwards said.
But the water-use efforts didn't stop with rainwater harvesting.
Although the Mushorns have a septic system for sewage, they diverted their greywater — the runoff from sinks, showers, and laundry — to give the native landscape plants a boost.
In addition to collecting rainwater, the roof holds enough solar panels to produce 11 kilowatts of electricity, which is more than enough to power the house during daylight hours. The Mushorns only need to purchase electricity after dark, resulting in an average electric bill of barely $70 per month.
But the solar panels aren't the only reason for the low electricity consumption. The entire layout of the house was intended to minimize energy usage.
Before they began designing, the team created solar studies to assess how the sun would hit the site during various times of the day and year.
As a result, the main axis of the house runs north-south, with the south-facing living room protected by a slatted patio roof that provides full shade in summer but allows more light during the winter.
Windows on the east and west sides of the house are small and deeply recessed so only a glimmer of sunlight penetrates, while the north and south walls feature clerestory windows that can open to allow hot air to escape and cool evening breezes to flow in.
The interior surfaces received similar consideration, and were selected to provide good indoor air quality.
The concrete floors don't off-gas, and the wood trim came from sustainable domestic sources. The paints were all low-VOC formulas, and the kitchen cabinets were purchased from a local company that doesn't use formaldehyde.
In recognition of all these efforts, the home was awarded a "Green Building" certification from the city of Scottsdale.
Over the 15 months it took to design and build the home, the Mushorns continued to collaborate with their design team on aesthetics as well as efficiency.
"It's good to have some time," Richard Mushorn said of the construction process. "You walk around and see something and say: 'Hey, I have an idea!' "
One of those ideas resulted in a series of steel art panels embedded in the rammed earth hallway.
Mushorn, who dabbles in metalwork, collaborated with Doug Edwards to design and build the panels, which feature cut shapes suspended within geometric frames.
Now that Richard Mushorn has finally retired, he and Lynn are enjoying the home just as much as they'd hoped. The garden is growing, the native plants are thriving, the electric meter barely moves, and if the irrigation ever breaks, there's a surgeon on hand to fix it.