AS THE GREEN BUILDING movement begins to bud, big builders face the task of figuring out just what kinds of green measures buyers are willing to pay a premium for. Will they really choose formaldehyde-free cupboards over marble floors, solar panels over bathroom suites? It depends. However, one aspect of sustainable design is fast becoming a no-brainer for builders and buyers: heating and cooling systems that reduce energy consumption. When folded into a mortgage, the added costs are balanced by lower utility bills, so they're easier on consumers' pocketbooks than other symbols of environmentally friendly design.

Not only that, but as prices for coal, oil, and natural gas soar, and as more and more builders extol their products' energy savings, it's only a matter of time before homes that lack high-efficiency HVAC systems will be rejected by savvy buyers. Ken Ford, program specialist for green building at the NAHB, estimates that more than 1,000 builders subscribe to environmental building programs. While that's still a sliver of the housing market, “it's something that builders nationwide have become cognizant of and are looking to do,” he says.

SIZE AND FUNCTION Of course, it's not enough simply to install a 90-percent-efficient furnace or a 13-SEER air conditioner sized to a house's square footage. Rather, a comprehensive approach to heating and cooling involves siting the house to its best solar advantage, using super-insulating materials and products, placing ductwork in conditioned space, and sealing off leaks.

ATTIC ADDITIONS: With the insulation at the roof sheathing, this conditioned space in the attic will be no more than 5 degrees warmer than the living space of the home. Jim Hackler, LEED Home coordinator at the Green Building Alliance in Washington, D.C., says green builders typically work with mechanical contractors who use Manual-J, a software program that calculates residential load by accounting for such features as climate, construction materials, and the house's orientation. Builders find that when they follow energy-saving principles on the whole house, they are able to save money by downsizing the HVAC systems.

“The calculation can be half the tonnage of what you thought you needed,” Hackler says. “It's very accurate, but builders have to stick to their guns and follow what it says.” He adds that an air conditioning unit that is too large doesn't operate efficiently because it kicks on and off, but a right-size unit will run nonstop on the warmest days of the year. Not only is it cooling the house, but it is constantly removing moisture so the air is cleaner and more comfortable. “The builders I know who have followed green HVAC standards have really reduced the number of complaints about comfort,” says Hackler.

Energy-conscious builders are tucking ductwork into conditioned spaces, avoiding kinks in the coils, and liberally applying mastic. But many also audit the work by conducting diagnostic tests that reveal hidden energy wastes—for example, a blower door test that measures the tightness of a building envelope, or a duct blaster test that measures ductwork leaks. Hackler notes that 20 percent to 30 percent of conditioned air in new construction is lost to leaky ducts. He says the tests typically cost $200 to $500, although many utilities do it for free or offer rebates to builders.

BRAND PROMISE Pulte's Tucson, Ariz., division has mechanical installations down to a science so that it can guarantee its homes' comfort and energy use. The builder randomly tests the homes for air tightness before they're Sheetrocked to ensure that duct leakage is less than 3 percent. When the houses are finished, they're checked again for pressure balance. It's part of the Environments for Living program by Masco Corp. that most homes in Pulte's Tucson subdivisions subscribe to. The builder spends $1,000 to $1,500 a home to incorporate such energy-saving measures as installing a 90-percent-efficient furnace and an air exchange system, and placing all ductwork within the pressure and thermal boundary of the building. As a result, the homes are built to 45 percent to 55 percent over Model Energy Code standards.

Brad Townsend, national sales manager for Environments for Living at Masco, says Pulte's homes save buyers $40 to $70 a month on utility bills. The builder also promises that no room in the house will be more than 3 degrees different from the thermostat temperature. At closing, buyers receive a certificate that lists the average kilowatts (cooling units) and therms (heating units) for their particular house plan. The owners save their bills, and if after a year they feel their home didn't perform as promised, Pulte will process a claim. “If the home goes over the projected energy use, we look at what they've paid on average over the year and reimburse them 100 percent of the difference,” Townsend says.

Education plays a key role in the program's success. The models include a display showing prospective buyers that air will travel through standard batt insulation but not the dense-pack cellulose Pulte uses. And a sign out front shows the monthly energy cost for that particular model. It seems the public is getting the message. “We are the only builder in Tucson doing this concept, and as home buyers shop the markets, they're seeing the value in this,” says Len Utt, Pulte's Environments for Living manager in Tucson. “We've even had home buyers going to one of the subdivisions where we're not doing an attic with cellulose insulation, saying, ‘I don't want to buy your house because the ductwork isn't in conditioned space.' ”

ENERGY EARNINGS: One of many ways to meet the energy requirements of the EarthCraft House program, this cost analysis shows that improvements in a building's envelope allow for a smaller air conditioner to be installed. By raising the price $700, the builder realizes a $150 profit, while the owner pays less to live in the house because utility costs go down. Haven Properties in Atlanta also has stepped up its homes' energy efficiencies. Four years ago the builder signed onto EarthCraft, the local green building program, and two years ago it added Energy Star specs to most of its products. Despite the fact that these measures add $4,000 to $6,000 to the cost of its homes (which range in price from $350,000 to $700,000), Dave Milner, Haven Properties' EarthCraft coordinator, says they add up to a “brand promise.” At the grand opening last April of the Tributary community at New Manchester, which is designed for Gen Xers, five sales in the first week were attributed to the builder's energy ethic.

“The developer's director of marketing said our reputation for energy efficiency had preceded us,” Milner says. “Gen Xers tend to be a bit more earth-friendly and seeking to conserve on utility costs. We felt like it was a nod that we were doing the right thing.”

The future of energy prices doesn't look good for homeowners. The U.S. is the single largest consumer of oil on earth, and our buildings use 35 percent of our nation's energy resources. Building homes that reduce energy demand is proving to be increasingly good for business, and good for the country too.