Industry professionals can help consumers improve their energy efficiency by understanding the need for controlling Air Infiltration. It's just as important as R-Value in the thermal performance of a building and the effectiveness of insulation. Infiltration of outside air means that heating and cooling systems must expend more energy to compensate for the infiltration. Cellulose Insulation impedes air flow, providing superior R-Value and minimizing air infiltration.
High-density cellulose insulation is extremely effective at inhibiting air movement. It seals houses better, limiting airflow through the insulating material as well as around difficult to insulate areas such as gaps around electrical boxes, wiring and plumbing.
Field tests have shown that blown in cellulose insulation can provide a building envelope seal that is 36% tighter than a fiberglass batt insulation seal.
To prove the point, a Canadian firm, Howell-Mayhew Engineering, conducted a test on a new cellulose-insulated home for air tightness. First the engineers measured air leakage after a polyethylene air/vapor barrier and before siding was installed. The engineers then slit the polyethylene air/vapor barrier in approximately 20 places and retested air leakage of the building. There was absolutely no change in measured air leakage. Additional Smoke Pencil Testing at the slits showed "not a breath" of air leakage.
(Sources: Consumer Update - Insulation Effectiveness Bulletin #4, A Public Service Publication Of CIMA)