The thermal performance of loose filled cellulose compares favorably
to other types of insulation. The thermal conductivity of loose-fill cellulose is approximately 40 mW/(K*m) (an R-value of 3.8 per inch) which is about the same as or slightly better than glass wool or rock wool.
This doesn’t represent the whole picture of thermal performance. Other important aspects are how well the building envelope
is sealed from air infiltration, convective airflows, and thermal bridging.
Cellulose is very
good at fitting around items in walls like pipes and wiring leaving few air pockets that can reduce the overall efficiency
of the wall. It also seals walls from air infiltration while providing the density to limit convection. The University of
Colorado School of Architecture and Planning did a study that compared two seemingly identical test structures, one with cellulose
and the other with fiberglass. The cellulose structure had used 26.4% less energy to heat. It also was shown to tighten the
structure more than 30%. Subsequent real world surveys have cellulose performing 20-30% better at reducing energy used for
heating than fiberglass.
Cellulose insulation is made from recycled paper that is applied as either loose fill into attics and closed wall cavities
or damp-sprayed into open wall cavities. Due to its recycled content and potentially higher energy and acoustic performance,
cellulose is an environmentally preferable product.
"11 minutes into the burn the ceiling of the uninsulated house collapsed....10 minutes later
the ceiling of the fiberglass house also collapsed. The ceiling of the cellulose house did not collapse until 1 hour and 10
minutes after the burn started."
-Insulator's Guide, news account of fire demonstration
Cellulose helps keep your home warmer in the winter, cooler in the summer,
blocks air infiltration, and saves you money!