By FRANCES ANDERTON from TheNyTimes.com

Residential architects in Los Angeles are experimenting with green design. Walter Scott Perry remodeled his 1950's tract house in the Hollywood Hills by reusing rather than replacing fittings and materials. He added solar panels and a sun screen, both purchased locally. With a rebate from the Los Angeles Department of Water and Power, his cost was around $12,000. David Hertz's home in Venice, Calif. — four buildings connected by bridges — has some roofs layered with photovoltaic cells and others engineered to generate hot water for washing and radiant heating.