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Fiberglass Vs. Cellulose Insulation

Insulation from cold, heat, fire, and acoustics is a necessity for the safety of buildings and homes. Fiberglass and cellulose, both serve the same function, and have some merits and demerits. This article distinguishes between these two types of insulation.

Insulation of homes is an important concern for builders and homeowners. Noise, is also a major disturbance in populated urban areas, where the influx of heavy traffic creates sound pollution. Designing any house or building, involves consideration of the best products available that provide insulation from fire and sound. Fiberglass and cellulose have been widely used for insulation. However, there has been an ongoing debate on their effectiveness. Health concerns, cost-effectiveness, durability, and environmental benefits, are the major issues that people generally consider before choosing either of these widely used insulators.

Information on Fiberglass

It is an artificial synthetic fiber that consists of calcium silicates, aluminum, and other metals. The process of manufacturing this glass is called Pultrusion, which involves fabricating linear glass fibers. It has been used since 1930s for insulation. Today, nearly 90% of North American homes are insulated. It is popular because of its cost-effectiveness, and it also helps the consumers to protect their houses from excessive cold and heat. It is also generally provided in the form of chopped fibers or sheets, and is yellow, pink, or white in color.

Information on Cellulose

It is basically glucose, which is tapped from recycled newspapers, magazines, and cardboard, which is treated with chemicals to produce an insulating material with varying properties. Materials are insulated by cellulose in many forms like spray-applied (wet-spray), stabilized, and low-dust cellulose. Fire resistant chemicals are added to it to increase the efficacy. Earlier, it was found out that when cellulose insulation was applied to wooden pipes and furniture, it attracted rodents. However, nowadays, addition of pesticides in such materials has controlled this problem.


The Differentiating Factor: R-Value

Before installing any insulating material, the key is to check its R-value. It is a number usually printed on the material, and is a measure of the material's ability to conduct thermal heat. The higher the R-value of a substance, the better are its thermally insulating properties. The R-value of fiberglass varies with its density. However, the R-value of cellulose is 3.7 per inch, whereas for fiberglass, it is around 3 or 4 per inch. But, the efficacy is determined by the overall R-value and not by the per inch value. Generally, fiberglass insulation has a higher R-value.

Energy Loss

There are various gaps, voids, and spaces present between the wall and the insulated material, which may not be visible to the naked eye, but they form a major factor in judging the performance of the insulators. A study has shown that cellulose has the ability to save 20% to 30% more energy than fiberglass. Air infiltration is comparatively lesser in cellulose than fiberglass. Soundproof recording studios also employ insulation in order to avoid noise. For example, in a recording studio, both materials are generally used.

Moisture Control

Fiberglass doesn't absorb water when wet, while cellulose shows these properties, owing to the fact that it's made out of recycled newspapers and cardboard. If the cellulose insulation becomes wet, chances are that its fire-retardant ingredients may wash away, and its R-value may also decrease. The cellulose does dry out and may regain its R-value, but it takes nearly two to three months for this process, once it gets wet.

Fire and Health Concerns

Fire safety is an essential parameter that judges the effectiveness of insulators. Fiberglass will not catch fire as it is made from molten materials heated to a very high temperature, giving it the properties of a glass. However, it does contain formaldehyde, which can produce toxic fumes in case of a fire. Also, if the skin comes in direct contact with fiberglass, it can lead to skin irritation, cuts, and rashes. The fiberglass is sealed in plastic cases so that during installation, there is no harm to the house owner or the workers. On the other hand, cellulose is highly flammable, and to reduce its impact in case of a fire, fire retardants are added to it. Boric acid, a poisonous salt found in cellulose, is harmful if it comes in contact with the skin. It is advisable that you wear safety masks while installing such insulators, as their dust may cause breathing problems.

Be it fiberglass or cellulose insulation, both are used all over the world depending on various factors, and it is always preferable that you seek an expert's advice before making a choice.