Nu-Wool claims WALLSEAL—an engineered spray-in cellulose insulation made of recycled newsprint—completely fills cavities to eliminate air infiltration. Rappe agrees, noting the fire- and mold-resistant product beats fiberglass batt in energy efficiency. Because it also resists air movement, the insulation makes a vapor retarder unnecessary, the company says. Nu-Wool, 800.748.0128; www.nuwool.com.
scott rappe, aia