You've heard of megawatts. How about negawatts? They don't exist in nature and you won't find it in the dictionary, but Acterra, the Palo Alto-based environmental nonprofit, is seeking to produce "negative watts" through free residential energy audits to cut electricity waste in high-end homes in five upper-income communities in the Bay Area.

Beyond having residents with large disposable incomes, these communities -- Atherton, Woodside, Portola Valley, Los Altos Hills and Monte Sereno -- are among the most prolific users of electricity in Pacific Gas & Electric Corp. territory, according to Acterra and based on PG&E's 2005 data.

Together, they are eligible for $166,000 in funds from the Energy Efficiency and Conservation Block Grant, a $3.2 billion program of the American Recovery and Reinvestment Act of 2009.

Each town has authorized Acterra to use its share of the grant money to conduct voluntary energy audits of large homes, including 240 in Atherton, 180 in Woodside and 150 in Portola Valley, according to program volunteer and Los Alto Hills resident Steve Schmidt.

Portola Valley has $25,000 available and the council voted 4-0-1 on Dec. 9 for the program after a presentation by Acterra representative Debbie Mytels. Atherton and Woodside have $40,000 and $30,000, respectively, and their councils gave their approvals in September.

(Portola Valley Councilman Ted Driscoll abstained. His venture capital fund, while not yet invested in any company with technology that Acterra may recommend to reduce energy consumption, does "actively invest in energy audit and energy efficiency companies" and thus could be invested in the future, he said in an e-mail.)

Recommendations coming out of the audits will be discreet, given the clients' privacy concerns, Ms. Mytels said. After an audit, electricity use tends to drop by 20 percent and natural gas by 10 percent, leading to annual savings of about $1,500, she said.

Signing up
The program works on the initiative of the homeowner to contact Acterra and sign up. Acterra will collect and analyze the data, make recommendations to the homeowner, then remotely monitor the home's utility bills for 12 months -- with the homeowner's permission.

For information, write to Ms. Mytels at debbiem@acterra.org and mention the High Energy Home program.

Audits will be progressively less personal, Ms. Mytels said. The first phase will include visits by Acterra volunteers. In the second phase, Acterra will interview residents by phone, and in the third, homeowners will enter the relevant information via the Web.

"How are you going to motivate people to actually do the work?" Councilwoman Maryann Moise Derwin asked.

"That's the real challenge," Ms. Mytels replied. It's important to "get a buzz going," she added, which might include signs in the front yards of program participants.

The profile for a typical California home shows heating water and heating and cooling the air using the most energy.

In large homes, Acterra's data shows greater consumption in the so-called plug-in load: extra refrigerators and wine coolers, home theater and whole-house audio systems, stand-by power for instant-on TV and audio systems, gadgets like towel warming racks, and heated spas, Ms. Mytels said.

"Maybe (the spa) doesn't need to be that hot," she said. "Maybe they don't need to have it on that many days of the year."

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