Blown Insulation: A Comparison Between Cellulose And Fibreglass

Home & Garden Blog

Blown insulation is made of loose particles that can be easily blown into a structure. The insulation is usually preferable for covering the space between the interior and exterior of walls, as well as covering hard-to-reach areas such as chimneys, attics or stove vents. This type of insulation is typically used on new structures as well as to add reinforcement to existing insulation.

Cellulose vs fiberglass blown insulation

There are basically two types of blown insulation; cellulose and fiberglass.

Cellulose insulation is made of pieces of recycled cardboard or newspapers that are blended with certain reinforcing chemicals, while fiberglass is made from tiny particles of spun glass fibers. If you are currently undecided on which of these two types of insulation to use in your home, here are two main areas of comparison that could help you make a decision.

Energy efficiency

The effectiveness of insulation to prevent air flow through your walls, floors and ceiling will usually translate in increased home energy efficiency. Fiberglass insulation has a lower R-value than cellulose, which basically means that it isn't as dense and will thus not be as effective as its counterpart in keeping out drafts in the attic or through the walls.

The lower density of fiberglass also means that the insulation has a tendency to be light and fluffy, which makes it difficult to form a continuous, even layer especially in tight spaces and around obstacles. This often results in small voids in the insulation, leading to energy inefficiency.

The higher R-Value of cellulose insulation makes it much more effective at stopping air transfer through structures, leading to increased comfort and energy savings. The dense nature of cellulose also makes it better at completely covering spaces inside walls and around tight spaces, as well as around obstacles such as pipes and ducts without leaving any voids.

Fire and insect resistance

Many homeowners tend to think that cellulose is flammable because it is made of recycled wood fiber products, but the truth is that the material is much more effective as a fire barrier than other alternatives. This is because the insulation is treated with borate, a highly fire retardant material that makes the insulation fire-proof. The borate chemical also makes cellulose resistant to pest and insect infestation, making it ideal for covering your attic, basement and other areas particularly prone to pest damage.

Fiberglass contains flammable elements that are used to hold the glass pieces together and give the insulation its color, making it prone to fire damage. The insulation also does little to keep out insects.

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15 September 2015