Oct. 25--Copeland and Christoph Casati love their midcentury modern home in western Henrico County.

They love the architecture, the layout, the gorgeous design. They hate the heating bills.

"We are paying thousands of dollars a winter to heat this house," Copeland Casati said. Worse, she said, "it's never comfortable, never cozy."

The Casatis, her husband said, declared war on their heating bill.

They brought in building-performance expert Guy DuBois with Commonwealth Building Sciences to do an energy audit of their home and find out where their heating dollars were going.

DuBois found "an extremely leaky house" with plenty of smoking guns: whole-house fan shutters that were venting warm air into the attic, air leaking from the crawlspace into the basement, and poor insulation in the ceiling of the added-on dining room.

Almost 45 percent of Virginians' annual residential energy bills go to warm their homes, energy officials said. The average household spends about $850 for heating.

Given the more than 3.2 million housing units in Virginia, that adds up to about $2.8 billion a year in statewide heating costs.

Those bills can be too much for thousands of Virginians to afford. Last year, 122,000 house holds received government help to pay their winter heating costs, said Andrea Gregg, energy-assistance program manager with the Virginia Department of Social Services.

Air leakage -- taking expensively produced warmth with it -- accounts for about 30 percent of heating expenses, Dominion Virginia Power says.

"The bottom line comes down to insulation," said Lee Householder, executive director of the nonprofit ElderHomes community-development organization. "The biggest thing you can do is insulating your home."

After that comes improving the efficiency of the heating system.

A basic step is having residential heating systems checked regularly, utility and equipment manufacturers say.

"Make sure the system's operating efficiently," said Jack Woodfin, executive vice president of the Woodfin Co. of Mechanicsville, which supplies home heating oil, equipment and services.

Dirty air filters, clogged oil spray nozzles, dusty thermostats and leaky ductwork all can rob systems of their effectiveness.

Besides installing high-tech insulating foam in the attic and replacing windows in a 1984 addition, architect Will Scribner has installed energy-efficient heat pumps in his 88-year-old North Side home.