Cellulose Insulation

cellulose insulation

Homeowners and contractors have also recently found the many benefits of insulating homes and buildings with cellulose. Cellulose insulation is plant fiber that is used in wall and roof cavities to insulate, draft proof and reduce noise in homes and buildings.

Thermal Performance

With regards to thermal performance, Cellulose insulation is generally superior to other types of low-cost insulation. The thermal conductivity of loose-fill cellulose is approximately 40 mW/m·K (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. Cellulose insulation can easily fit around objects in walls (pipes, wiring), without leaving many air pockets. When densely packed, cellulose insulation can seal walls from air infiltration, while also limiting convection. 

Long-term Cost Savings

How much can you expect to save in costs? It depends. Annual savings from cellulose insulation is dependent on many factors, including: insulation thickness, local climate, heating and cooling use, original wall performance, and more.

Sound Insulation

Cellulose insulation can reduce sound traveling through walls and between floors. The density of cellulose gives it an advantage over other forms of insulation, such as fiberglass. Cellulose insulation works to reduce the lateral movement of sheetrock, which decreases the amount of sound that can travel through walls.


Vapor Barrier

A vapor barrier may not be needed with cellulose insulation. For example, recent studies have shown that air movement is the primary method by which excessive moisture can accumulate in mild marine climate such as Portland, OR, USA.[7] An insulation that fills the wall cavity completely (such as cellulose or foam) can help prevent moisture problems. Recommendations against using vapor barriers with cellulose insulation are supported by studies, even though they classify cellulose as vapor permeable.

Mold and Pest Control

The borates in cellulose insulation provide added control against mold. Installations have shown that even several months of water saturation and improper installation did not result in mold.[6] It is a common misconception that the mere presence of crude borates in cellulose insulation provides pest control properties to the product. While boric acid itself does kill self-grooming insects if ingested, it must be presented to an insect in both sufficient concentration and in an ingestible form in order to achieve insect fatality. Proper testing of products containing borates must be performed in order to determine whether dosage and presentation are sufficient to kill insects. Once tested, registration with the EPA as a pesticide is required before a product may be touted as having pesticidal capabilities in the USA.

Fire Retardation

The borate treatment also gives cellulose the highest (Class I) fire safety rating. Many cellulose companies use a blend of ammonium sulfate and borate.