Earth shelter

An earth-shelter home is unusual. And a home that has power but is completely off the power grid isn’t something you see every day. But an earth-shelter home that’s off the grid? Jena Pittmon isn’t sure, but she thinks there could be just one. Five years ago, Pittmon, partner Lee Pittmon and Albert Lassiter bought 10 acres of bare land in a remote area off the west side of Lake Coeur d’Alene, and spent two years building an earth-shelter home. They planned to use alternative energy as a primary power source, but when they discovered it would cost $30,000 to extend power lines to their property, they decided to generate their own power. “We are our own power company,” Jena Pittmon said. The two-level, three-bedroom home is powered by a 5-kilowatt solar energy system and a 1-kilowatt wind generator. On sunny days, the system provides enough energy for the household, with surplus energy feeding a large bank of batteries, Pittmon says. In summer, the system has so much surplus energy that they try to find ways to use it, like operating an electric rototiller in the garden. When it’s cloudy, dark and there’s no wind, they have a propane-powered generator that helps keep the lights on. All told, Jena Pittmon said, they are generating about 80 percent of the power they use. They have a separate solar-energy array that powers a water pump, which transports water from a well to a 3,000-gallon storage tank. A separate solar water heater provides domestic hot water. In addition, the home has what’s called an Annualized Geo Solar heating system. This experimental system gathers heat during the summer and passively releases that heat in the fall and winter. They powered up the system late last summer, and they believe it will provide a greater benefit as time goes on. The home is designed to conserve energy as well. They have motion sensors on the indoor lights, and they use energy-efficient bulbs throughout the home. “While we sometimes enviously drive by our neighbors and see all the lights on, we want to conserve,” Jena Pittmon said. “If everyone used power with an awareness of where it’s coming from, we wouldn’t have some of the problems we’ve had with power.” Even if it hadn’t cost so much to bring electricity to the property, they would have employed alternative-energy generators, she said. Their previous home in Post Falls has a large wind generator that provided a lot of the energy they used. It was nice to generate energy while on the grid, she said, because the power company would let them run their meter backward, dramatically reducing their power bill. The new house has some intrinsic energy-saving qualities. Being surrounded by earth on three sides, the temperature is more constant than an above-ground home where the walls are constantly exposed to the elements. Lee Pittmon says that if one turned off the electricity entirely and left the home for a year, one would return to find the temperature hovering between 55 and 60 degrees Fahrenheit. The home, on which Lee Pittmon acted as his own contractor, includes two concrete domes that include a total of 4,000 square feet of floor space. The larger of the two domes includes two floors with 2,500 square feet of space and houses the living room, kitchen and three bedrooms. The smaller dome has a shop on the main floor, with studio space above it. Jena Pittmon operates her Web-design business out of the studio space—the business, Open Ears Web Design (www.openearsweb.com) has an office in Coeur d’Alene as well, but she works primarily from home. The space is large enough for the band called Positive Shift, in which Pittmon plays bass, to practice. A 14-foot underground tunnel connects the two domes, and another tunnel leads to a back door. To build the home, they leveled part of the hillside, then created a metal shell with four layers of rebar and wire-reinforced netting on the interior. Once that was erected, concrete was poured onto the structure, about 4 inches thick on top and 12 inches thick at the base. The structure was sprayed with a polyurethane foam insulation and a waterproofing agent, and the netting inside the home was pulled off. Once complete, dirt was pushed back onto the structure. Realizing there wasn’t nearly enough earth to cover the home, they bought 30 bales of recycled tires as fill material. Each bale has 300 tires in it, so there are a total of 30,000 old tires surrounding the home. The dirt then was pushed atop the bales, and natural grasses now grow there. Some of the tire bales can be seen from the front of the house, between the two domes and flanking their sides. “They are ugly,” Pittmon said. “We are discussing various ways to cover them, which we hope to do this year.” Because they are their “own power company,” they monitor energy usage and supply more than a typical homeowner does. In the tunnels, monitors tell how much energy is being produced and what the charge levels are on the batteries. The solar panels’ angle must be adjusted four times a year to correspond with the sun’s position in the sky. That typically occurs in the middle of each season, Pittmon said. While more work, it’s well worth the effort, they said. “Since we had a burning passion for alternative energy, we decided we could spend less to create our own power while reducing our impact on the environment,” Pittmon said. “The challenge is stimulating and fun.”