The tour, and tours held in Boulder and Estes Park this weekend, offered the public a unique chance to see old, new and not-quite-completed homes and buildings with features that take advantage of Colorado's bountiful solar resources. If you're bummed you missed the events, don't worry, they were just three of 14 being held throughout Colorado between now and October 9 as part of the American Solar Energy Society's (ASES') 2010 National Solar Tour, which is hosting 270 events this year and is expected to have roughly 160,000 attendees.
The Denver area tour, which was organized by the Colorado Renewable Energy Society, is in its 15th year, explained CRES Executive Director Tony Frank. "We want to help people understand how to make smart energy improvements to their homes." he said. "Many people care about the future, the environment and energy use. This is a way to show people they can act locally and take action on their own home."
It's a given that adopting solar power is still costly, and you're not going to find a solar array for your home at Kmart anytime soon. But the solar system on the green luxury spec home in the Genesee Estates development barely added to its $1.6 million price tag. In fact, about $45,000 of the $65,000 solar heating systems were related to solar thermal heat, which is used to provide radiant floor heat for the 4,117 square foot house. A photovoltaic and solar hot water system for the home would have added about $20,000 to the home's price tag, agreed Matt Johnson, co-owner of Namaste Solar and Scott Carpenter of Simply Efficient, which installed the systems. They added that the PV system would pay for itself in about 10 to 12 years.
The house was built by A.D. Wolff & Associates, Inc. Real estate agent Michell Juneau, who showed the home, said Wolff "thinks that anything over $1 million should have solar" and be sustainably built.
But going green in your home doesn't have to be extravagantly expensive or require building a new home. Energy-efficient retrofits at Steve Stevens' 1979 ranch-style home in Golden were done on the cheap. Stevens, who holds two penny-farthing bike Guinness World records, has converted his inefficient home into a building that makes more energy than it needs, largely by doing it himself and using insulation scraps and lightly damaged pieces he buys for much less than retail price. When he bought the home in 2001, he calculated his energy use produced 14.8 tons of carbon dioxide annually. With his retrofits, which include a PV system and a solar thermal system and his use of an entirely electric Prius, his carbon footprint is at negative 6.6 tons of carbon dioxide annually, which means he's producing significantly more power than he needs and selling the excess to Xcel Energy.
Brent and Mo Nelson (both National Renewable Energy Laboratory employees) recently remodeled their 1956 brick home. "The insulation was horrible," Brent said. They added proper insulation, a 5.7 kW photovoltaic array and a solar hot water to their home. The array has amorphous silicon and crystalline silicon photovoltaic panels. Amorphous silicon has some advantages, it "takes less energy to manufacture, it can be put into a flexible package, is low weight" and can be made in various shapes, Nelson explained. "But the big disadvantage is efficiency. Crystalline silicon modules are much more efficient," he added.
Ron and Gretchen Larson showed off their award-winning home on Lookout Mountain. It won the 2002 Solar Decathlon held in Washington, D.C. Larson, a former ASES chairman and board member of, and founder of CRES is also a former electric engineering professor at Georgia Tech. At 77 he'd just returned from Brazil where he was learning about biochar which was practiced hundreds of years ago, where waste wood is smoldered until it turns to ash and then used as rich fertilizer. In modern applications, it can store carbon dioxide and provide power generation as well.
Larson said he and his wife bid on the home in 2001, because they always wanted a solar home, and the University of Colorado project needed additional funding when it was being built. After winning, the Larsons built an extension compatible with the existing structure between 2004 and 2005 and "moved in in 2005." The home has a 7.5 kW photovoltaic array and solar hot water. The wood-heated home took about three-quarters of a truckload to keep warm in 2009, Larson said. He explained that the home's walls were 10 inches thick and provide significant insulation, but if he had it to do over again, he would have used 12-inch thick walls for even more insulation, to reduce heating needs.
Perhaps the most relaxing, inviting home on the tour was the Moore residence, a 3,500 square foot Santa-Fe style oasis complete with a waterfall. We saw hummingbirds among the flowers as we walked up. The home was built as a net-zero energy retirement home for Ann and Mike Moore. "We will be here when we die," she said.
She designed the Weego baby carrier, which won a Best of Westword award in 2002. Ann said that building the home as a net-zero home added about 17 percent to its cost, but they believed they "needed to be as environmentally responsible as possible." She also noted that the home's 10 kW photovoltaic array, solar hot water system and geothermal heating system should pay for themselves within 10 years. With rising energy prices "we'll probably get it back quicker," she added. The couple met in the Peace Corps and said they are committed to doing "anything we can do to make us more environmentally aware."