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Photo of the University of Colorado's competition-winning house integrated into the Larson home in Golden, Colorado. Enlarge image

BASE+ has been integrated into the home of Ronal and Gretchen Larson in Golden, Colorado.
(Credit: Carol Anna/U.S. Department of Energy Solar Decathlon)

Who: University of Colorado at Boulder
What: BASE+ House
Private residence
Golden, CO 80401
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Public tours: Call the Colorado Renewable Energy Society hotline at 303-806-5317 for information about the annual Denver-Area Solar and Green Homes Tour.

Solar Decathlon 2002

University of Colorado at Boulder: Living in a Panorama

The University of Colorado won the first U.S. Department of Energy Solar Decathlon with its BASE+ (Building a Sustainable Environment) house. Originally designed as an adaptable construction model, the house was later integrated into the home of Ronal and Gretchen Larson on Lookout Mountain above Golden, Colorado.

Dr. Larson got to know the University of Colorado team in 2001 after having spent almost 30 years in the solar energy field. As a congressional fellow in 1973–74, Dr. Larson played a part in the first two solar energy bills passed by Congress. He then taught electrical engineering for 10 years at Georgia Tech before becoming a branch chief in July 1977 and, later, the first principal scientist at the Solar Energy Research Institute (now the National Renewable Energy Laboratory). Dr. Larson also helped establish a renewable energy technology center in Sudan that is still operating today. His interest in and support of the Solar Decathlon team grew out of these experiences.

"I was involved in student competitions while I was at Georgia Tech," says Dr. Larson. "I understood the amount of work required by students and faculty advisors."

BASE+ returned to the University of Colorado campus after the competition on the National Mall. Rebuilt near the Benson Earth Sciences Building, it was used for research, teaching, and outreach activities for almost one year before being offered for sale. The university accepted sealed bids from July 3 until Aug. 22, 2003, and then awarded the house to Dr. Larson.

The Larsons purchased a lot in Panorama Estates, a residential community atop Lookout Mountain. They then enlisted the help of Walt Kaesler and Doug Larson to serve as primary architect and builder, respectively. Their combined expertise created a 2,700-ft2 residence out of a 660-ft2 house.

Although the floor plan is almost unrecognizable as a Decathlon house, almost all of the BASE+ components were kept. The solar panels, evacuated tube solar collectors, and 1,000-gal domestic hot water tank remained with the house, as did the appliances, lighting, and furniture. Even the original batteries are still used to store energy.

However, Dr. Larson tinkered with the house over the years. He added more solar thermal panels and a two-compartment 10,000-gal water tank because of his keen interest in thermal storage. He also installed four windows in the unheated, upper-level garage with R-values ranging from 2 to 11 so he can compare their performance. Furthermore, he's considering the addition of a greenhouse to increase the house's passive solar capabilities.

"We've certainly had power when no one else did," says Dr. Larson. "But otherwise, the house is a lot like a regular home."

The Larsons have hosted more than 1,000 visitors as part of the annual Colorado Renewable Energy Society solar home tour.