Eric Feldt Sr. has seen nearly every brand of vinyl siding introduced during his 30 years as a siding installer. But he's never been more impressed than he has been with the newest category of the product known as insulated vinyl siding.

“It creates very straight walls and offers high impact resistance, which is important in this area,” says Feldt of Affordable Window and Siding in Ann Arbor, Mich.

Larry Etman, co-owner of Fairfax, Va.-based Better Homes Remodeling, agrees. “It's shaped to the contours of the house, and it's very firm so it won't push in if it's knocked into,” he says. Etman recommends insulated products to his clients, although he installs traditional vinyl siding as well.

Feldt, on the other hand, only applies insulated products because he says they can withstand the harsh weather conditions Michigan sometimes offers up. The siding installer's insulated vinyl projects cost about $450 a square foot installed, 25 percent to 30 percent more than regular vinyl jobs.

A relative newcomer to the market, insulated vinyl siding has rigid foam laminated to the back of its panels. The backing increases the siding's R-value by as much as five times that of conventional backings, which manufacturers claim helps reduce homeowners' energy bills. As important, it blocks out noise and improves the home's appearance because the panels don't cup and won't dent, manufacturers claim. And like standard vinyl, insulated products don't require painting or staining and are low maintenance.

Pat Culpepper, president of Progressive Foam Technologies, the extruded polystyrene (EPS) foam backing manufacturer that's the major supplier to the vinyl siding industry, contends that insulated vinyl is an obvious choice for the remodeling market. But he says it will make inroads into new construction during the next two to three years because production builders want to set themselves apart from their competitors.

One Florida builder, for example, offers clients insulated siding as an upgrade. “When panels overlap and you don't have [foam], they can gap as heat causes them to expand. The backing keeps them stiff and makes the siding look better,” says Stephen Drake, director of purchasing for The Villages active-adult community in The Villages, Fla.

Although insulated siding was introduced to the market by Crane about six years ago, most brands were rolled out during the past few years. Crane and most other siding makers use Fullback by Progressive Foam to insulate their products.

In recent months, Alcoa launched Structure, an insulated siding that features Dow's Styrofoam-brand extruded polypropylene (XPP) backing. Justin Lucas, owner of a roofing and sheet metal distribution firm in New Jersey, installed Structure on his home last summer. “The seams lay tight and the backing doesn't flake apart,” Lucas says. “It has the best resiliency.”

Linnea Johnson, marketing manager for Alcoa's vinyl products, claims Structure's XPP backing retains R-values better and is 30 percent more impact resistant than standard EPS foam. But Structure also is 15 percent to 20 percent more expensive than EPS-backed products, she notes.

Culpepper of Progressive, which also provides the service to laminate the Dow XXP backing to Structure for Alcoa, says when installed beneath vinyl siding on a building, Progressive's EPS foam does not absorb moisture and thus its R-values don't deteriortate over time.

No matter the type of backing, insulated siding will continue to swell in popularity, industry officials predict. “Each traditional vinyl siding manufacturer is either adding an insulated line or expanding existing insulated product lines,” comments Culpepper.

As product choices proliferate, pros hope prices will fall. Insulated vinyl products cost about the same as wood and fiber-cement sidings. “All of my clients want insulated vinyl, but not all can afford it,” remodeler Etman says.

The Dark Side

White and beige always will be the most popular siding hues, but vinyl siding manufacturers are adding deeper shades to their collections as color technologies improve.

According to Mark Axelrod, director of marketing for Crane, newer ASA (acrylonitrile/styrene/acrylate) formulations and other acrylic polymers and resins allow siding makers to create darker colors that are more resistant to UV rays. Crane, for instance, recently introduced Cypress green to its palette.

Allen Duck, marketing manager for Heartland, claims that the new formulations, like Heartland's Composite Technology program, not only offer better color retention, but greater heat resistance so that the siding won't distort.

Nevertheless, darker colors aren't for every home. Replacement contractor Eric Feldt Sr. says he only offers a handful of dark hues because his clients prefer lighter shades.

Plus, says Larry Etman, a Fairfax, Va.-based remodeler, strict homeowner association regulations often dictate color options, and many of the rules require pale colors.

What's more, Feldt hesitates to install dark tones because he worries that in 10 years they might not be as vibrant—despite comprehensive warranties offered by most siding makers.

“Manufacturers don't have time-tested proven products yet,” he cautions.