Last month Brian Dunbar, director of the Institute for the Built Environment at Colorado State University, invited me to listen in as his graduate students in construction management presented case studies on green homes. I enjoyed learning more about Dan and Karen Cripe’s home in Round Rock, Texas, which student Jeff Wilkes describes as “green, but normal.” Dan and Karen made some relatively large upfront investments in solar panels and energy-efficient upgrades when they built the home, and now they’re seeing the rewards. Their January utility bill was $3.64.
The 1,852-square-foot home, designed by Debra Blessman of Select Home Design and built by Wayne Jeansonne of Solluna Builders, was built for about $300,000, excluding the lot and the solar PV. It achieved a 5-Star rating from the Austin Energy Green Building rating system.
The owners wanted a home that looked like all the other homes in the neighborhood but with sustainable features. Because they plan to spend the rest of their lives in the home, they were happy to pay now for the infrastructure that would help them minimize energy costs in the future. Their goal is to produce all of their own energy; the home is entirely electric because gas could not be generated on site.
Dan and Karen wanted to build in an established neighborhood, but because many homeowners’ associations prohibit solar panels and metal roofs—both key features of the home—they had their work cut out for them in looking for a lot. The lot they found had southern exposure and a few mature trees, which the city of Round Rock was going to require that they take down before building (city codes mandate removing any tree within 36 inches of the foundation). Dan and Karen obtained special permission to save the trees, and the lot’s southern exposure provides optimal direction for solar PV.
The low-maintenance home will be easy to take care of as Dan and Karen age, with lots of open space for ease of movement throughout. Concrete floors are easier to move on than carpet, especially in a wheelchair, and light switches are low for easier reach. Throughout the design process, the couple added and deleted features based on their budget. Ceiling heights, for example, were lowered from 9 feet to 8 feet to save money throughout
High-efficiency water fixtures, including dual-flush toilets, are used throughout the home. A 500 gallon rainwater collection system collects rain that falls on the roof’s back slope. Rain that falls on the roof’s front slope is directed through gutters to a rain garden, which helps slow the flow and prevent erosion. The runoff is then diverted to naturally irrigate the native, drought-tolerant landscaping in the front yard. The owners say that keeping deer from eating the plants is a bigger challenge than getting them to grow with little water.
Energy conservation and renewable energy generation were high priority. A geothermal exchange system utilizes two 1-inch diameter pipes drilled 270 feet into the ground to regulate the water’s temperature. This heat exchange drives air conditioning in summer and heat in winter and supplements the hot water heater.
Open cell bio-based foam insulation is used throughout the house, providing R13 value in the walls and R20 to the roof. Solar tubes throughout the home provide natural light and reduce the need for artificial lighting. A 5 kW solar PV system, purchased with the help of local rebates, cost Dan and Karen less than $10,000—making it an investment they couldn’t pass up.
“Dan plans to retire early, so he focused on what it costs to own and operate this home — for him, it’s about the bottom line,” Karen explains. “As for me, I’m an old tree-hugger—I’m more concerned about wise use of the earth’s resources and doing the right thing for the environment. We came at this from different angles, but in the end, we wanted the same result.”
Dan and Karen Cripe were committed to making their home energy independent. A solar PV system on the heat-reflecting Galvalum metal roof provides nearly all of their power. Locally quarried Texas limestone was used on the exterior finish.
Recycled quartz countertops and low-VOC finishes were used in the kitchen.
Operable windows and ceiling vans allow for natural light and ventilation. The home’s open floorplan is accessible to wheelchairs.