There are a lot of hybrid dogs these days. You know, cockapoo (cocker spaniel and poodle), Labradoodle (Labrador retriever and poodle), and Shepadoodle (German shepherd and poodle). These animals make wonderful pets because they combine the best features of both breeds.

The hybrid of the exterior products category, insulated vinyl siding, combines the benefits of two materials to make an even better product. According to manufacturers, insulated brands inherit the durability and energy efficiency of a foam backing and the easy care of a vinyl material.

“It's the best of both worlds,” says Gary Cutler, a partner in Kear and Cutler Builders in Greenville, N.C., who installs traditional and insulated sidings.

And it's easy to install, pros say.

When insulated vinyl siding was introduced on a large scale in 1998, it was met with resistance because it was misunderstood, says Pat Culpepper, president of Progressive Foam, which supplies many vinyl siding makers with the foam backing for their insulated products. Nevertheless, it's quickly gaining fans in an industry of slow adapters.

Traditional vinyl siding sales total about 35 million squares annually, compared with 1 million squares for insulated vinyl siding, according to industry experts. But because of its inherent attributes, significant growth is forecasted. Business consulting firm Hadley Associates predicts insulated vinyl siding sales will double to quadruple during the next five years.

A number of years ago, some vinyl siding makers produced a simple drop-in insulated product, with a separate foam backing dropped behind the vinyl during installation. The newest designs have an attached foam backing, which, makers claim, provides a tighter fit enhancing the home's energy efficiency.

The foam's rigidity has other advantages, according to builder Cutler. Insulated vinyl siding is not as brittle in the winter months, he says, and won't buckle in the summertime.

Furthermore, insulated products also are more impact resistant than regular vinyl, and help deaden sound, according to manufacturers.

The development of the laminated foam backing allowed the product “to go beyond the boundaries” of its ancestors, says Mark Axelrod, director of marketing for Crane, which was the first to introduce an insulated siding.

These expanded boundaries include wider board faces. According to Axelrod, traditional vinyl siding only can span up to 10 inches wide. Crane, for example, can offer an 18-inch-wide insulated product because the strength of the foam permits longer boards that don't bend. The result is a siding that looks more like wood, says Axelrod.

WHAT'S YOUR TYPE? There are two types of insulated sidings available. Most are backed with extruded polystyrene (EPS) provided by Progressive Foam. There also is a product by Alcoa backed with Dow Styrofoam extruded polypropylene (XPP).

XPP is “more forgiving” than EPS, making it easier to handle in the field, claims Alcoa vinyl product manager Linnea Johnson. But Culpepper says EPS and XPP are “practically similar products on the wall,” although EPS is more rigid, helping the siding lay flat.

Vinyl siding makers say both XPP and EPS closed-cell foams don't absorb moisture, but some are making design changes. Crane is enhancing moisture and mold resistance with SmartTrak, a system of diagonal channels that allow the release of trapped moisture. Meanwhile, Royal Building Products says the foam backing with ventilating air pockets on its DuraPlank product is locked, not glued, to the siding, which leaves room for expansion, contraction, and the escape of moisture.

Manufacturers say they're pursuing ways to make the foam backing thicker, hoping additional energy savings will justify high prices. Existing brands can save homeowners up to 25 percent on their annual energy costs, producers say, but cost about 25 percent more than regular vinyl. That's why it's used primarily in remodeling.

But sales may begin to swell in the new home market, manufacturers predict. “If energy costs continue to be as high as they are,” says Johnson, “consumers will try to cut bills any way they can, and insulated vinyl siding will be a perfect solution.”

Royal Building Products. DuraPlank's foam backing is locked to the siding, which, according to the maker, leaves room for expansion, contraction, and the escape of moisture. As the thickest panel available, the firm claims this insulated vinyl siding is 300 percent stronger than the ASTM industry standards. Insulated window casings and outside corner posts also are offered. 800-387-2789.

Crane. The solid-core backing of CraneBoard, at a 4.0 R-value, deadens noise up to 45 percent better than traditional vinyl, the firm says, as well as bolsters the home's energy efficiency. Because of the additional backer, thermal conductivity is diminished, claims the company. The insulated vinyl siding is offered in 6- and 7-inch panels with triple 6-inch and double 7-inch options. 800-366-8472.

Mitten. InsulPlank insulated vinyl planks are installed in a lapping method that produces an even appearance, according to the firm, and are specially treated for insect and mold resistance. The manufacturer says the siding also applies flat, concealing any wall imperfections. The product comes in 10 standard colors, and a complete line of matching trim is available. 800-265-0774.

Heartland Building Products. The firm believes in the energy-saving capabilities of its CedarMax Thermal Siding so strongly that it guarantees the homeowner 20 percent energy savings, up to $500, for the first year after installation. Its polymer formulation results in long-lasting performance, the maker says, while reflective technology prevents the color from fading. The panel is available in double 6-inch clapboard and triple 4-inch Dutchlap profiles. 800-432-7801.

Alcoa. The DreamColor system allows the homeowner to customize Structure insulated vinyl siding to match any cus- if local building codes allow, the maker says. The panels come in four colors: Sierra slate gray, Quaker tom color using its 700 baseline colors. As the first siding backed by Dow Styrofoam, the insulated vinyl siding also green, Vermont blue (pictured), and Sequoia red. 800-641-4691. Circle 156. improves the home's R-value up to 25 percent and diminishes noise by as much as 50 percent, the manufacturer says. The firm also claims the siding locks securely for installation. 800-962-6973.

Certainteed. TruComfort insulated vinyl siding comes in three styles: double 6-inch cedar board, double 4-inch clapboard, and double 4¼-inch Dutchlap. It features a 1¼-inch rigid foam backing that increases the R-value up to 22 percent, while reducing heating and air conditioning costs and noise, the maker claims. 800-233-8990.