By Linda L. Leake |
The Monument’s Painted Hills Unit is named for its natural stratifications of yellow, gold, black, and red. It includes 3,132 acres of scenic marvels, including this one—a two-bedroom, one-bath home set in an area rich in fossils, yet functioning without benefit of fossil fuels. In fact, with the recent donation of a fully electric utility vehicle from Polaris Industries, the entire park is now completely fossil fuel-free—not including energy burned by the park’s 130,000 annual visitors.
The home is fully solar-charged, with 5.6 kW of PV panels, along with a solar hot water system. The 24 PV panels generate about 7,000 kWh of power annually. Excess solar electricity charges the Polaris EV LSV electric utility vehicle, which the ranger uses to drive some 5,300 miles each year. Additional spare power will energize a nearby information kiosk.
“This was the number of miles our initial calculations showed we could operate a Chevy Volt in one year using only the surplus power of the initial 24 panels,” says Ted Clifton, principal of Zero-EnergyPlans.com and the ranger house designer.
“We used the Volt as our model, because at the time it was the only electric vehicle to have a U.S. Environmental Protection Agency mileage rating. I suspect the Polaris vehicle would get higher mileage, because it is smaller, but the terrain at the park is more rugged than the average street or highway, so who knows--there is no measured history for this vehicle.”
Ted Clifton of Zero-EnergyPlans.com reports that the park staff will be keeping careful records of the mileage and energy production of the home, as they have thus far. “Actual measurement of the energy production to date indicates that the home is producing more than twice as much surplus energy as our energy models predicted,” Clifton says. “That is fairly typical with my designs, as the computer programs do not do a very good job of calculating passive solar gain. The RemRate program also did not give us full credit for a solar hot water heater that produces 100% of the hot water needs of the house year round.”
South facing windows in the home optimize passive solar gain in winter, while overhangs reduce gain during hot summer months. The south roof includes ample space for the large solar array.
“The house is clearly out-performing our expectations thus far, producing and returning to the grid almost three times as much energy during the day as it draws at night, even during the cold winter months,” Clifton says.
Completed in December 2010, the home cost about $200 per square foot in hard costs. Clifton spent that money carefully on high-performance products. For example, he specified structural insulated panels (SIPs) from Big Sky R-Control, which make the home very tight--a total of about 1.2 air changes per hour at a pressure of -50 pascals. The concrete slab is fully insulated with rigid foam to R-20. There’s an additional R-10 of foam insulation at the perimeter of the slab, down to 2-ft. depth--appropriate for this climate.
The ductless mini-split heat pump has a heating seasonal performance factor (HSPF) of 10.1. This system doubles as a low-energy air conditioning system for swing seasons. Fan-Tech add-on units provide high efficiency particulate air (HEPA) filtration and heat recovery ventilation (HRV).
Other energy-saving features include triple-glazed low-E windows with U-values of .20 and a solar heat gain coefficient approximately .25. The home’s insulated fiberglass doors offer a U-value of .16. A solar hot water heater and drain-back system work in tandem with a hig- efficiency 80-gallon storage tank.
In addition, all construction waste was hauled to the contractor's sorting facility in Bend, Ore. Careful attention was paid to flashing details and drainage at windows, doors, and at foundation insulation. Low-flow fixtures and faucets are standard, and all landscaping was done with native vegetation, transplanted from elsewhere in the park, in compliance with the strict guidelines of the U.S. Park Service. No watering is required.
Clifton says the house could have been built for about $50,000 less, had it not been for the special reinforced foundation required in the volcanic ash soils of the Painted Hills area. The final contracted amount was $278,000.
Kirby Nagelhout Construction was the company that contracted the construction of the house for that amount. Clifton was hired as the designer, and for certain project supervision responsibilities during construction. “As a general contractor, I have priced this house out as if I were building it in my own neighborhood, and it comes in around $200,000,” Clifton relates. “The remote site added a lot to the cost, as did the expansive volcanic soils. The government’s Design, Bid, Build process also contributed to the higher cost of the project. Private industry, working for private individuals, can always build the same product for less--especially if design-build is the delivery mechanism.
“This house was about dialing the numbers in,” Clifton says. “If there was a way to crank the energy-use lower, without significantly raising the price, we did it. And we are still dialing.”
To view this article as it appears in our July 2011 issue, with additional photos and product information, please visit our Magazine Archive.