To figure out how to make her house more comfortable and energy-efficient, Cupertino City Councilwoman Dolly Sandoval accepted an invitation from the nonprofit California Building Performance Contractors Association to assess her house on Alderbrook Lane.

Sandoval said her 50-year-old ranch house, which has no air conditioning, is extremely hot after 4 p.m. in the summer. Sometimes she has to keep the fan running until midnight to cool the house down.

So on July 22 Sandoval opened her house to two heating and ventilation contractors. The visit is part of the California Home Performance Program, which evaluates homes for energy efficiency and trains contractors to identify and fix problems. This is also the state's first initiative approved by the Environmental Protection Agency's Energy Star program.

Right now the program is only available in Fresno and Santa Clara County. Sandoval's house is one of 50-plus houses that have received an energy-efficiency examination through the program.

The specialists started their test by touring Sandoval's house.

"By walking throughout the house, we find out the owner's concerns and get a general idea of the layout of the house," said Rick Chitwood, field trainer for contractors.

After three hours of inspection, the contractors found that Sandoval's house is more energy-efficient than most 50-year-old houses, but like many old houses, her air duct has serious leak problems.

Sandoval and her husband, Ed Hoffman, moved into the house eight years ago. They are the third owners of the three-bedroom, two-bathroom house. The environmentally conscious couple installed double-pane windows and a new furnace in 2000.

The double-pane windows are effective in reducing heat loss, but the furnace is too powerful for the 1,100-square-foot house, said Greg Torre of ACE Heating & Air Conditioning Inc. of San Mateo. And the stacks for the furnace are made of three different materials, which cause condensation and shorten the life of the furnace.

Torre relied on experience when evaluating the furnace's combustion efficiency but he had to use sophisticated equipment like infrared cameras and duct blasters to identify the exact locations of the leaks.

After taping the ducts and decompressing the house to measure air flow, the contractors found the air duct is too small for the house and leaks 58 percent of the heat. The duct in the attic and the skylight shaft in the kitchen need proper insulation. They also discovered a wall between the bathrooms that is not insulated, and since the bathrooms have no exhaust fans, they don't have enough fresh air.

The contractors recommended Sandoval install a new furnace, replace the duct system, insulate the wall between the bathrooms and install a translucent plastic panel below the skylight shaft in the kitchen. They also suggested that she add air conditioning.

"There is no obligation to make improvements, but homeowners do find they can slash their utility bills up to 40 percent," said program director Steven Sokolsky. "If the owner decides to improve the house, a test will be conducted after all the improvements are made to make sure we meet the goal."

In Sandoval's case, if she follows all the suggestions, the contractors estimate her house can increase heating system efficiency by 50 percent, reduce heat loss by 23 percent, and improve indoor air quality by 80 percent. The mold in the bathrooms will also be eliminated. The improvements might cost between $5,000 and $10,000.

Sandoval was impressed by the result. She said she would consider installing a new duct system but air conditioning might be beyond her budget. She also encouraged other Cupertino residents to take advantage of the program.

"A significant number of houses in Cupertino are fairly old," Sandoval said. "Such an assessment would be valuable in making old houses more energy-efficient."

Census data show three of every four homes and apartments in Cupertino were built between 1950 and 1980.

The diagnosis can cost between $100 and $300, but the program is offering a flat rate of $100 until Aug. 14.

Although the program targets houses that are at least 10 years old, program officials urge owners of new homes to have their houses diagnosed.

"New homes have many architectural features and this architectural complexity makes it difficult to insulate new houses," Sokolsky said. "We have found the average air flow loss rate of a house, no matter if it is old or new, is about 30 percent."

"Our house is made of many systems, and they are all related to each other. The key word is performance," Sokolsky said. "We cannot build more power plants, but we can make the existing homes more energy-efficient, more comfortable and healthier."

For more information about the California Home Performance Program, call 888.352.2722 or visit http://www.calhomeperformance.org.