Straw-bale construction suddenly seems new and savvy again as the California energy crunch grinds on. The age-old building material is being used in many structures, from homes and offices to barns and meditation centers.

Builders and architects who work with it say there are probably more than 250 straw-bale structures in California now, more than double the total from just a few years ago. And the number is growing steadily, as more people discover the rewards of using golden bales of rice straw to build.

Straw-bale homes' thick walls help conserve energy. They provide a practical use for rice straw, a waste product that farmers often burn. The stuccoed bale walls keep sound out and often have a softer, more natural look than traditional drywall.

"Unless you're European, you're not used to thick-walled houses, and the big surprise is that they have a lot of presence," said John Swearingen, owner of Skillful Means, an architecture and building company that specializes in straw-bale construction. Indeed, people who live in straw-bale homes say it's hard to describe the sense of quiet and calm that walls two feet thick -- the width of an average bale -- can give to a house.

People have used straw as a building material for thousands of years, usually mixing it with mud. Building with bales began soon after the invention of the mechanical baler in the mid-1800s, and several straw-bale homes built in Nebraska in the early 1900s still stand.

But most people unfamiliar with straw-bale construction express doubts when they first hear about it. Can it be made earthquake-safe? Will it be consumed by insects? Won't it burn down in seconds if there's a fire? Won't the straw begin to rot in wet weather?

The answers are yes, no, no and "only if you leave it uncovered for months and months in the rainy season."

Building with straw bales is permissible in any California county, although the technique seems to be most popular in the Gold Country and Napa and Sonoma counties. Straw bales are featured in a house under construction in the Santa Cruz Mountains, a just-finished office building at Hidden Villa children's camp in Los Altos Hills and several homes in Oakland and Berkeley that are showing the building technique to new audiences.

A 1995 state law established optional guidelines for cities and counties to follow for permitting straw-bale construction, and a new bill sponsored by state Sen. Byron Sher seeks to update that law by simplifying some guidelines. The Senate is expected to vote on the bill this month.

Newcomers to the world of straw often assume that building with bales will be cheaper than erecting a timber-frame house, but that's not always the case. Walls go up fairly quickly, especially if you invite friends for a "bale-raising" party, but the process of finishing and stuccoing the walls takes a lot of labor and time, which adds to the cost.

Also, said Maurice Bennett, president of the California Straw Building Association, rice straw is up to more than $4 per bale in the state. His 2,000-square-foot home in the Sierra foothills used 513 bales.

If the owners of a new straw-bale home did none of the work themselves, he figures, their home will probably cost 10 percent to 15 percent more than a conventional wood-frame one.

But the savings on energy costs might eventually make up the difference.

Straw-bale walls are roughly twice as good an insulator as conventional framed walls, said Martin Hammer, an architect who has designed straw-bale structures.

In a home with straw walls but conventional flooring and roofing materials, residents might save as much as 25 percent on their heating and cooling expenses, he estimates.

Joshua Lichterman and his wife, Holly Leeds, chose straw-bale for their new home because they wanted to build from a renewable resource, he said, but the energy savings are turning out to be a benefit as well. "It's particularly wonderful given the recent energy crunch," said Lichterman of his two-story, 3,000-square-foot home near Grass Valley. "We didn't know we would care as much as we care."

Many straw-bale structures have "load-bearing" walls, meaning the stacked-up bales are supporting the weight of the roof. Other buildings use wooden posts and beams to enhance the seismic safety of the building. In either case, bale walls are typically pinned to the home's foundation with steel, then covered with wire mesh and coated with stucco. Interior and exterior surfaces usually maintain the slightly uneven texture of the bale.

"The sort of organic shape of the walls is really nice, they're sort of curvaceous," said Eugene de Christopher, who is building a 900-square-foot cottage on property he and his wife own in Berkeley. De Christopher started the project in July 1998, and has done almost all of the work himself.

The cottage was designed by DSA Architects, a Berkeley firm that has extensive experience designing homes and other buildings from straw bales. DSA's Dan Smith said the flexibility afforded by straw is one of its most attractive characteristics.

"You can use a chain saw or Weed Eater or even a kitchen knife and shape the edge of the bale" into curved forms, he said.

Yet, bale walls are so compacted that they are inhospitable to both insects and fire.

"The core is like a phone book, it's too dense to support combustion," Smith said.

Although straw-bale construction is catching on in California, especially in the past several years, the technique is still far from mainstream. Many municipal building officials still need convincing to appreciate the qualities of straw bales.

"They start asking all the normal questions about moisture and insects and fire, but there are answers for all those questions," Hammer says. "But most people just look at it and it captures their imagination."

Leif "Hal" Rovick is one of those. He began building his 1,000-square-foot straw-bale barn and workshop in Soquel last May.

"I like simple things that are old but new," said Rovick, a carpenter. He and his family also enjoyed the spontaneous community that sprang up around their "barn." The building is on busy Old San Jose Road, and while the walls were going up, strangers stopped by to see what was going on and to help. "We must have had about 150 people just pull over and say, 'What's this? What are you doing?' " Rovick said.

In the past, straw-bale homes appealed primarily to environmentally conscious homeowners who liked the idea of building something practical and durable out of a waste product.

But straw is also increasingly popular with "modern, computer-age professionals" who work in stressful environments, said builder Swearingen. Straw-bale homes can be "like an old comfortable coat," he said, "sort of an antidote for the other parts of these people's lives."