Synthetic Stucco Siding Is More Energy Efficient
Traditionally, stucco is a mixture of lime, cement, sand, and water that is applied in three coats over mesh or lath, and then if needed is coated with an acrylic polymer that prevents cracks from forming in the stucco. Synthetic stucco siding has a foam insulation board, generally polystyrene, and coats of synthetic stucco over a fiberglass mesh. It is finally finished with a topcoat.
This stucco looks identical to traditional stucco but will be softer than it. Wire mesh in the stucco indicates that it is traditional, as different from the foam you will see if you drill a hole in the stucco.
The synthetic variety of stucco is more energy-efficient than traditional stucco. Both of them are fire-resistant, create a barrier to sound, and also come in a variety of colors and finishes.
Synthetically made stucco can be slightly more expensive, but the energy efficiency more than offsets this.