From the driveway, the house looks like just another new four-bedroom, two-car garage model with considerable curb appeal.

Inside, construction on the 3,000-square-foot home in Ellicott City is in limbo, a strip of insulation cut away here and an attic baffle or two removed there. Numbered signs filled with diagrams and descriptions are tacked up at 14 different locations.

But the home is neither abandoned nor in foreclosure. Instead, it has been serving as a test site for homebuilding techniques that slash energy consumption.

Built by Columbia Builders Inc. in the Stonehouse Overlook neighborhood, the Baltimore Gas and Electric Co.-sponsored pilot home is a two-story laboratory of sorts, built to the specifications that will be required of Energy Star homebuilders in 2011.

Fifty area builders, energy experts and product suppliers from the Baltimore area recently toured the house off Route 99 to learn how to make new homes more energy efficient.

Energy Star, which most consumers associate with energy-saving appliances, is a program of the U.S. Environmental Protection Agency. Use of the blue logo, which amounts to a government seal of approval, was first extended in 1995 to homebuilders who met EPA criteria.

"Without knowing it, I had been building homes that met or exceeded Energy Star guidelines for years before they even existed," said Jim Greenfield, president of Columbia Builders. In business since 1975, the company joined the government program last year.

So when BGE decided to set up three pilot homes in Maryland that would adhere to next year's Energy Star building code, Greenfield agreed to build one of them. The others are in Towson and Bel Air.

Columbia Builders managed to construct a home that's nearly 25 percent more energy efficient than current Energy Star code requires, said Greenfield. Current Energy Star homes must be 15 percent more efficient than their non-Energy Star counterparts."That means this house is using nearly 40 percent less energy than a standard code-built home," he said. "This is huge."

These energy-efficiency ratings are calculated by third-party energy experts "to prove that what we're saying we do we are actually doing in reality, which is awesome," he said.

The combined effect of all these improvements is far from lost on industry insiders.

"Jim's pilot home is head and shoulders above what we were expecting," said Rick Gazica, a builder account manager for Columbia-based ICF International, which is implementing the pilot program for BGE. "Everyone who saw it was really impressed."

The motivation behind constructing pilot homes is the EmPOWER Maryland Energy Efficiency Act of 2008, Gazica said. This act calls for a 15 percent reduction in per-capita electricity consumption and peak demand by the end of 2015, according to the state government Web site.

Rolling brownouts are a possible outcome if consumption isn't reduced, he said.

BGE launched its Smart Energy Savers Program on June 1, 2009, spurring the construction of 49 Energy Star homes by 28 homebuilders in the area last year, as well as commitments to build another 1,700 in 2010, said Ruth Kiselewich, BGE's director of energy-efficiency programs.

The program provides incentives to businesses and consumers, she noted.

"BGE is measuring the true energy savings and will have the results in the second quarter," she said, noting the company's recommendations for modifying its incentive program to meet the new Energy Star standards must be approved by the Maryland Public Service Commission.

"We want to push the envelope on energy efficiency," said Kiselewich, adding that BGE is one of five utility companies participating in the pilot program.

To reduce energy consumption by such a high margin on its pilot home, Columbia Builders used a number of creative construction strategies, Greenfield said.

These include a modified Arkansas truss system to lessen air loss at the top of exterior walls; a new method for installing insulation that eliminates trapped air under drywall; and building 4-inch dummy walls around plumbing to provide a double layer of insulation where cuts around pipes would normally allow air to enter.

"Maintaining the integrity of the thermal envelope that surrounds a house is what it's all about," the homebuilder said. With these new features in place, it's like the home is protected by a hidden force field that's impervious to air and water.

"Air leakage is a major enemy of energy conservation and water leakage in walls reduces the effectiveness of insulation in trapping air or preventing it from getting in," Greenfield said.

"If the thermal envelope isn't penetrated, the home will act like a beer cooler - able to keep beer cool in summer and coffee warm in winter, too," he said.

Despite what would seem to be an obviously desirable set of green features, some homebuyers think they can't afford an Energy Star home, said Thom Marston, an independent energy rater for Energy Services Group in Wilmington, Del.

Marston, who calls what he does "finding any weak links in a home's energy armor," said that type of thinking is annoying to him.

"In reality, the energy savings per month are greater than any additional financing costs that might be incurred" by a homeowner who opts for an Energy Star package, he said.

"A house like this allows its owners to move their energy-savings dollars into their mortgage payments and have a more energy-efficient, comfortable and durable home," Marston said. "Who wouldn't want that?"

Greenfield echoed that sentiment, saying he has opted to become a 100 percent Energy Star builder, which is a yearlong process, and beyond that to have all of his homes rated to guarantee that he's providing a uniformly efficient product, which is not required by the EPA.

"I want to verify how we did on each home and to be able to catch any human error that might otherwise not be caught," he said. "It's like doing a project in school and not getting a grade - I want to know what the grade is on every house I build."

The Stonehouse Overlook pilot home will remain open by appointment to interested builders for one more week, Greenfield said. For more information, go to www.columbiabuildersinc.com and click first on Maryland single-family homes, then on Lakeview, and then on "contact us."

Energy Star statistics for Baltimore 6,260 qualified homes built to date

0 qualified homes built in 2010 to date

572 qualified homes built in 2009

80 Energy Star builder partners

Energy Star-qualified homes built in 2009 are the equivalent of: Eliminating emissions from 280 vehicles

Saving 1,695,408 pounds of coal

Planting 463 acres of trees

Saving the environment 3,325,036 pounds of carbon dioxide

From the energystar.gov Web site