Cellulose Vs. Fiberglass Blown-In Insulation: Which is Best For the Attic?

In life, everyone has to choose what’s best for them. But sometimes, that decision isn’t so simple, especially when it comes to caring for your home! You could be considering insulating your attic but are unsure which one is better: cellulose vs fiberglass insulation. Many would argue that one is better than the other and list the benefits. We’ll be fair and break it down for you. 

Most homes in Georgia use fiberglass insulation. The second most popular insulation is cellulose. Which gets you thinking. Both can insulate well, meaning lasting comfort and spending less on heating and cooling. But which is best for the attic? cellulose vs fiberglass insulation. Let’s discuss!

Choosing the Right Insulation Material for Your Attic

First of all, any insulation is better than no insulation. That’s the very simplest answer. Whether you choose cellulose or fiberglass, the most significant achievement would be that you decided to insulate your attic. However, you might want to consider several factors before choosing the best option for your home. And additionally, regardless of the option you choose, if the insulation is not installed correctly, the insulation values will be poor!

But let’s start with the basics. The R-value determines the thermal performance of an insulation material. The higher the R-value, the higher the level of insulation from the material. Loose-fill cellulose boasts an R-value of 3.2 to 3.8 per square inch, while loose-fill fiberglass settles at 2.2 to 2.7 per square inch. Therefore, cellulose has a higher R-value. Yet despite its lower R-value, fiberglass is the most preferred option in Atlanta and across Georgia. 

Blown-in cellulose insulation is made from recycled materials.

Pros & Cons of Cellulose Insulation

If you plan to insulate your attic, cellulose is one of the best options. It’s made from recycled denim and paper which makes it environment-friendly. Before you choose the option, knowing the pros and cons of cellulose insulation is vital.


  • It provides high heat resistance due to its density. Due to its high level of heat resistance, it has a high R-value.
  • It helps save the environment from mountains of discarded paper, denim, and cardboard that end up as discarded waste from paper manufacturers. 
  • Cellulose is treated with boric acid, which resists mold growth and insect infestation. It also increases fire resistance from the insulation material. 
  • Blown-in insulation is useful, especially in your attic, and very affordable to manage.
  • The health risks involved with cellulose are fewer than those related to fiberglass. 


  • Installing cellulose can be costlier than fiberglass. 
  • It produces lots of dust during installation, which can be messy and hazardous to the installers if they are not adequately protected, especially with a breathing mask. 
  • The dry-blown cellulose sags and settles over time and reduces its R-value. You’ll be forced to install another layer to increase the R-value.
  • All cellulose insulation types require a vapor barrier. Otherwise, they’ll fail later. The material absorbs moisture quickly. 
  • It requires specific equipment to help with the installation. It can’t be DIYed.

Pros & Cons of Fiberglass Insulation

Fiberglass is an alternative to cellulose insulation. The blow-in insulation option for your attic has its advantages and disadvantages. It’s up to you to overlook the disadvantages and go ahead with the insulation material or use cellulose over fiberglass. Here are the pros and cons of fiberglass. 


  • Fiberglass insulation is inexpensive and very effective when added to your attic. 
  • The material is energy efficient and helps cool your home when it’s hot, keeps it warm when it’s cold, and reduces heating and cooling bills. 
  • Fiberglass is fireproof and can stop a fire from spreading in your attic. 
  • About half of the material is recycled, while the other half is manufactured from sand, which makes it renewable. 


  • Fiberglass settles and sags if blown in, decreasing the R-value with time. 
  • It becomes wet, which reduces its insulation values and leads to mold growth.
  • Fiberglass is less dense, and creating an air-tight seal can be time-consuming. It’s not the best for preventing air exchange.

Cost Comparison of Cellulose and Fiberglass Batts

Both fiberglass and cellulose are the least expensive options in the world of insulation. Their prices are almost the same, costing about $0.30 to $1.50 per square foot. However, cellulose insulation may require specialized skills, making it slightly costlier depending on the professional company doing the job. 

Environmental Impact Of Both Types Of Insulation

Cellulose helps lower carbon emissions by utilizing waste materials like paper, denim, and cardboard. It reduces the amount of paper waste in landfills and lowers our homes’ carbon footprint. Besides, it also allows you to save on energy. 

Fibreglass is made from sand indirectly. Sand makes glass. Recycled glass materials are used to build fiberglass. The insulation material contains 40-60 percent recycled material. Fiberglass is not biodegradable, which is now what we would want for our environment. 

FAQs: Cellulose Vs. Fiberglass Blown-In Insulation

What type of blown insulation is best?

Spray foam is the best option for your attic, but it’s expensive. However, if you prefer the more affordable blown insulation, fiberglass is the better alternative to cellulose. 

Can you put too much blown insulation in your attic?

Too much of something can’t be good, and that applies to blown insulation in your attic. If you add too much, it will cause more harm than good.

Which insulation is best for an attic?

Fiberglass or mineral wool is the most suitable material for attic insulation. 

Find Your Ideal Insulation Type with Us

When it comes to comparing the two materials, there’s little difference in terms of costs or performance. However, if you want long-lasting insulation, you might want to consider spray foam. Though it can be expensive, it has zero environmental effects, offers a higher R-value, and will last about 100 years. Contact us, and we can advise you on the best choice for your home and budget. We are the insulation experts in Georgia, and always at your disposal.

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