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She has written ten books, including the award-winning The Business Guide to Sustainability. Hitchcock also taught in the Bainbridge Graduate Institute's Sustainable MBA Program. After moving with her husband, Dale Graham, and their dogs, from Portland, Oregon, to Northern Arizona in 2013, Hitchcock settled into a condo. The family soon discovered, however, that they needed one more bedroom. Plus, the condo didn't align with their sustainability values.
They began their search. The couple wanted to stay in the same neighborhood in the Village of Oak Creek, in part because the homeowners association (HOA) included membership to an adjacent fitness club and spa they enjoy. "Beyond that," Hitchcock says, "we needed solar access, meaning a southern exposure so that we could design a passive-solar house. It would be stupid not to. It's free energy."
I feel I have to earn my place on this crowded planet
Darcy explains. "If you're building new, it helps to have a set of priorities. I had four: climate change, energy, water, and fire. Obviously, in the Southwest, they are all interconnected."
Designing to the Site
After finding a lot, Hitchcock set to work designing a 2,225-square-foot sustainable home for the family. "Because of the lot's topography, I needed a long thin house with a garage on one end, the master bedroom away from the spa parking, and most of the living space to the south for solar access," she says. "I started with a plan that met those criteria." She hired a local builder interested in sustainability. His designer helped finalize the plans.
Hitchcock also divided the lot into sections according to functionalities. "The lot is rectangular," she explains, "so the north part is in the front yard. The second quarter is the house. The third quarter is the back patio, which we fenced off so the dogs can run around but not get into the fourth area, intended for food production. Otherwise, one of our dogs would stand on her back legs and eat my raspberries!"
There are two natural wildflower areas. "I felt horribly guilty about taking another chunk of land away from nature," she adds. "I wanted to give as much of it back as I could. A strip along the south wall in the fourth section is all pollinator plants." There's also a big, natural area in the front. "When you grade the land, you end up with a lot of fist-sized rocks. We raked those into one area and gave it a nice edge, and on dog walks, I'd gather wildflower seeds that I tossed in there. We now have wildflowers blooming from spring to fall."
Hitchcock also successfully estimated how much overhang she'd need for solar heat gain in the winter and shading in the summer. "I put the sunroom in the middle of the house, and had to guess how much overhang we should have, and it turned out about perfect. In the middle of the summer, we get about half-an-inch of sun in the room. In the winter, the sunlight reaches beyond sunroom deep into the house."
ICF and Sustainable Systems
Hitchcock and Graham considered rammed-earth and straw-bale construction but nixed both ideas because of the HOA. They also considered aerated concrete blocks that the Navajo were making with fly ash from their coal-fired power plant. The couple decided the thermal mass of the ICFs made with recycled styrofoam from a Phoenix company was a better and more sustainable product.
Called EF Block, the ICF includes 87 percent recycled material. It's also fire resistant to 2,300 degrees, and therefore met one of Hitchcock's four main priorities. "The manufacturer takes recycled styrofoam that's been used as packaging, breaks it up into little pieces, and mixes it in a slurry of cement," she explains.
"They build it like a series of Lego blocks," she adds. "They stack the blocks, insert rebar, and pour in the concrete." One drawback? "If you want to hang something on an exterior wall, like a flat-screen television, it's hard to find the concrete. We used special hangers for the cabinetry in the kitchen."
A grid-tied 20-panel solar array on the roof provides all they need for their energy-efficient house. The home averages 12 kWh per day versus 32 kWh per day for the average Arizona home, which includes the HVAC and charging their Chevy Volt. The only thing that isn't electric is a natural gas fireplace, which the couple uses sparingly on winter mornings.
A geothermal system with a heat pump takes care of heating and cooling. "My original idea was to have heating and cooling in the floor because I've heard how wonderful that is," Hitchcock says. "But I was told cooling might lead to condensation on the floor. Also, when my husband looked at the boiler system and pipes necessary to do subfloor, hydronic heating, it seemed like a big risk to have all of that water going through the house. It was much easier to make the home all-electric and put up solar panels."
Camille LeFevre
Camille LeFevre is an architecture and design writer based in the Twin Cities.
