[5] He next entered graduate school at the University of Chicago, and studied particle physics under Enrico Fermi, a Nobel Prize-winning Italian physicist.

[5][7] In 1954, after earning his Doctor of Philosophy in physics, and with a recommendation from Fermi, Rosenfeld accepted a position as a teaching physicist at the University of California, Berkeley.

A turning point in his career came as a result of the second Arab oil embargo in 1973, when he realized that one of the key vulnerabilities of Americans was their inefficient and wasteful use of limited energy.

At the same time, California utilities were projecting a 7 percent annual growth in electric demand, and were planning to build a number of nuclear power plants along the coast.

To organize a team of scientists to work on it, he established the Center for Building Science at Lawrence Berkeley National Laboratory, which he would lead until 1994.

[12] The center under his leadership developed a number of energy efficiency technologies, including heat trapping window coating and compact fluorescent lights.

"He truly shaped the way an entire generation of researchers and policymakers worked together to conserve resources," said Berkeley Lab director Mike Witherell.

That led to breakthroughs in not only low-energy lights, but also windows, refrigerators, air conditioners, and other appliances, along with the design of entire buildings.

[1] It led to California becoming a model of energy conservation for the nation, and in 1978 it was the first state to approve a strong energy-efficiency building code, called Title 24.

[15][16] Other states and countries became aware that although homes in California were loaded with new energy-consuming appliances, such as computers, large-screen TVs, iPods, PlayStations, central air conditioners, hot tubs and swimming pools, their per person energy use had remained the same as it was 30 years earlier.

[5] Those standards impacted various industries: New homes and buildings were required to have better insulation and to be fitted with energy-saving lights; heating and cooling systems had to be more efficient; appliances were redesigned to use less power; and utilities were told to motivate their customers to use less electricity.

[5] Rosenfeld acted on his basic principle: "Conserving energy is cheaper and smarter than building power plants.

While the pressure to build nuclear facilities was growing as the population grew, utilities and policymakers began to agree that new power plants were not always needed.

The resistance from utilities and manufacturers was eventually overcome when it was calculated that those new standards had yielded billions annually in energy savings for California consumers.

Governor Brown subsequently set up California's first Energy Commission, requiring as part of its mandate the use of the new efficiency standards for buildings and appliances.

[18] In 1980 Rosenfeld helped form the American Council for an Energy-Efficient Economy (ACEEE), a non-profit organization aimed at promoting energy efficiency policies and technologies.

[19] At that event, Rosenfeld said that his own inspiration for establishing the organization was his "fury" at president Jimmy Carter's plan to spend $88 billion on alternative fuel development, but almost nothing toward energy conservation.

[7] In later years, he was a leading advocate for the use of white or light colored roofing materials to reduce building cooling costs.

[13] Former U.S. secretary of energy, Steven Chu, explains that by Rosenfeld's calculation, having white roofs on all flat-roofed buildings and for pavements, would be the equivalent of removing all the cars in the world for 18 years.

[23] He is survived by two daughters, Dr. Margaret Rosenfeld at the University of Washington Children's Hospital in Seattle and Dr. Anne Hansen at Harvard Children's Hospital in Boston; His sons-in-law Professor Daniel S. Weld, University of Washington, and Professor Jonathan Hansen, Harvard.