With oil prices reaching $50 per barrel for the first time late last month,the old real estate adage of "location, location, location" is being joined by the new mantra of "energy saving, energy saving, energy saving."

Increasingly, trend-setting builders are offering buyers new houses with solar technology that generates enough electricity to meet half or more of a home's needs. "Finally, people are starting to pay attention, and it's because energy bills are going up," said Joyce Mason, vice president of marketing for Pardee Homes. Pardee, a division of lumber producer Weyerhaeuser Co., has long been a major builder in San Diego and a leader in adopting energy-saving technology.

And in older homes, energy upgrades such as new windows and furnaces are considered the minimum divide between a ready-to-live-in house and a fixer-upper.

In Sacramento, Gov. Arnold Schwarzenegger has made solar energy a key plank of his legislative agenda, but a comprehensive plan to spur construction of solar homes died in the final days of the last legislative session.

Instead, a stopgap measure to continue funding of solar rebates for homeowners was signed by the governor on Sept. 30.

The state's building industry, which worked with Schwarzenegger on the failed bill, expects the push for solar homes to be revived next year.

"The goal is to offer it to every consumer. But you have to have the maufacturers ready to deliver and cities and counties willing to modify their design requirements to allow it," said Tim Coyle, senior vice president of the California Building Industry Association.

Perhaps offering a preview of the future, the two-story houses in Pardee's Soleil at Bordeaux project in Carmel Valley at first look like many others on the market, with composition-tile roofs, stucco walls, high ceilings and big windows to let in San Diego's generous amounts of sunlight.

But there's more under the skin, with high-tech equipment that can reduce energy use in the house to a net zero from the estatlished power grid. "San Diego is uniquely located to alternative-energy systems," said Beth Fischer, Pardee's vice president of community development.

Along the new state Route 56 corridor, Soleil is just far enough inland to avoid the coastal fog. The new-home community is the first in San Diego County to earn a U.S. Department of Energy classification as zero energy.

Under the department's Zero Energy Home program, builders combine the latest in energy-efficient construction and appliances with renewable energy systems such as solar water heating and solar electricity that are available in the marketplace.

Like most homes, a Zero Energy Home is connected to the utility grid, but can be constructed to produce as much energy as it consumes annually, for net zero consumption overall.

As buyers take the Soleil model tour, they stroll through the "LIVINGSMART® Room," with displays that show just how different these homes are from conventional houses. Along with information on insulation, a tankless water heater and other "green-built" features, a digital readout shows the model home --- air conditioner humming, lights ablaze during the day, refrigerator running, audio system playing --- is using 5.089 megawatts of electricity.

An adjacent readout shows the home's solar collection system is generating 2.175 megawatts of electricity on this bright, sunny day.

That shows that a bit more than half of the power is coming from --- and being billed by --- SDG&E. The rest is coming from the sun, through a photovoltaic system integrated into the roof tiles that turns sunlight into power.

If the appliances had been shut down, cutting energy use to a minimum, the excess power would feed into SDG&E, which then credits the homeowner's account.

Pardee estimates that with all the energy-saving features in place, energy consumption is reduced by 75 percent over a home meeting California's current building-code standards.

The subdivision was designed so that 125 of the 129 homes are able to have the solar panels. All can be built with the tankless water-heater option and other energy saving features.

All this does come at a cost, of course. The energy-saving features are standard on a third of the homes and a $12,000 option on most of the others. Houses in the development are priced from $800,000 to $900,000.

In a real estate market such as San Diego's, where until just recently, homes have been routinely been snapped up by buyers, it's hard to tell if the energy packages are an important selling point. Fischer said there were 300 applications for the first 11 homes released at Soleil.

But the company's not yet convinced that the high-tech options are selling. "This is a good, strong market," she said, but "we don't know yet if people are opting for it."

At least two visitors to Soleil said energy efficiency is important to them. "Absolutely," said Sharon Brambir, who was touring the development recently. Saving dollars on energy was just as important to her as cutting pollution by using the sun to create electricity, rather than burning fossil fuels. "I'm surprised more builders don't do this," she said.

Robert Laberge said he wasn't looking to buy at Soleil, but he wished his existing home in Poway had some of the energy features. "I'm ecologically oriented --- this would appeal to me," he said. "I'm interested in doing some of this (on my home), but older houses are tough to do anything with."

Over the last two years, Fischer said Pardee's other homes have also been built to higher energy standards than the building code, reducing usage by an estimated 10 percent over comparable homes built to the state standard.

These homes, dubbed "LIVINGSMART®," meet the U.S. government's Energy Star program for home builders and include appliances as well as construction techniques that reduce energy usage. In construction, features include ductwork that's sealed and inspected to ensure that hot or cold air does not escape.

Scott Anders, policy and planning director for the San Diego Regional Energy Office, lauded the efforts of local builders Pardee and Shea Homes, as well as apartment builder KD Development, in adopting energy-saving technology. The energy office is a local nonprofit organization that manages $30 million in public funds to help reduce energy usage.

He said the easiest way to reduce energy usage within houses is to adopt more stringent requirements on new construction, although these have generally been opposed by builders as singling out their industry.

As some home builders look more to adding energy options in their homes, the movement has also attracted apartment developers.

In the San Carlos neighborhood of San Diego, KD Development is building a 180-unit apartment complex which, like Soleil, is using photovoltaic cells and energy-saving windows, classified Low E2, that filter ultraviolet radiation and which use argon gas between the panes to keep temperatures in check.

KD's project also has hydronic heating, which uses a tankless water heater to heat the home as well as water for washing and bathing. "I'm worried about our power future," said Mike Turk, the company's president. Turk started creating energy-efficient developments in the 1970s, when the state of the art was unsightly roof-mounted solar water heating systems that frequently leaked. "Everything I build now gets photovoltaic cells and is Energy Star rated," he said. "They get net metering --- they sell back to SDG&E." The solar system generates electricity during the day, when family members are at work and school; after the sun goes down, energy credits pay for electricity. "They put money in during the day and draw it out at night," said Turk, who is a member of the city of San Diego's Sustainable Energy Commission. In August, the 1,500th customer connected to the utility's grid.

Insulation at the project is rated R-19 in walls and R-30 or more in ceilings, exceeding California's minimum of R-11 walls and R-19 to R-30 in ceilings.

On the resale market, Turk says if prices soften, energy efficiency --- especially zero energy usage --- will be a real asset. And while the direction of house prices may be in doubt, there is strong evidence that energy prices will remain on an upward course. "In a slower market, this will make a difference," Turk said.

Jack Brandais is a San Diego-based freelance writer. Contact him at mail@weekenddriver.com.