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Fiberglass vs Cellulose Insulation

Fiberglass vs Cellulose Insulation

July 5, 2019

fiberglass vs cellulose insulation

Insulation. If you’re thinking, “it’s all the same to me,” you are not alone. In fact, most homeowners have trouble understanding what type of insulation is right for their home and family.

It’s helpful to compare different types of insulation to decide what material is right for you. So, the DFW Thermal team has assembled this list of criteria on which you can compare fiberglass vs cellulose insulation. Read on to find out more!


Cost is the first factor on most homeowners’ minds when comparing insulation. On one hand, fiberglass insulation can be blown-in or pressed into your attic and walls as batts. On the other hand, cellulose insulation , can only be blown in. Blown in fiberglass insulation and blown in cellulose insulation are nearly identical in cost, about $0.70 per square foot. However, fiberglass batts are less expensive, costing only $0.40 per square foot.

But, it is essential that you base your choice of insulation not only on price, but also on a material’s effectiveness.


Every type of insulation has an R-value. R-value is a rating that indicates how well an insulation prevents hot air from entering your home in the summer, and warm air from leaving your home in the winter. Fiberglass and cellulose insulation have similar R-values of between 3.5-3.7.


Fiberglass insulation is made of tiny shards of glass, and as such is completely non-flammable. On the other hand, cellulose insulation is made from paper. While this paper is treated to be flame-retardant, there are some reports of it catching fire in extreme heat.

Air Leakage

Neither cellulose, nor fiberglass insulation are a barrier to air flow. However, when comparing fiberglass and cellulose, cellulose insulation is much denser and therefore more effective at slowing air.

Over time, fiberglass insulation shifts and compresses, leading to thin spots and holes. This makes your home even more vulnerable to unwelcome hot or cold air. Luckily, cellulose insulation does not shift or compress as drastically, preventing air leakage.


Fiberglass batts are the easiest type of insulation to install. In fact, most homeowners can install batts themselves. However, without a professional it is easy to leave holes and gaps in your insulation. These holes and gaps let air-conditioned air escape, wasting your money. As for blown in insulation, fiberglass and cellulose are nearly identical. Although it is possible to install blown in insulation without a professional, most opt to call an insulation expert.


Because it is made of paper, cellulose is vulnerable to prolonged contact with moisture, and could possibly develop rot, decay, or mildew. While fiberglass is not as likely to develop rot or mildew, it will lose R-value over time if exposed to moisture.

Health Issues

Cellulose does not pose any health risks to homeowners or their families. Fiberglass insulation on the other hand, is a potential carcinogen. But, if you are interested in installing fiberglass insulation, there is no need to be concerned. If those installing your insulation use proper safety equipment there is no risk.

Environmental Concerns

If you are concerned with your insulation’s impact on the environment, cellulose is the superior option. Cellulose insulation is made from 85% recycled content and will not pollute the environment in manufacture or use. Fiberglass is only 50% recycled and will pollute the environment during manufacture and use.

Decided between fiberglass v. cellulose insulation? Call DFW Thermal today for installation.

We hope this guide has helped answer some of your questions about fiberglass vs cellulose insulation. But, if you want to know more, call DFW Thermal today. Our team proudly insulates the DFW community with high-quality products and customer service. Call us today at 214-731-3115, or schedule your appointment online.