Cellulose Vs Fiberglass Insulation: Which Is Best?

Not sure which type of attic insulation is best for your home? We will compare the pros and cons of two of the most popular choices: cellulose and fiberglass insulation.

What is the best attic insulation: fiberglass or cellulose? This one is a tough call. Either cellulose or fiberglass insulation can give you significant energy bill savings by decreasing your home's energy consumption.

Both fiberglass and cellulose offer different styles to cater to every attic need. Fiberglass has rolls, batts, and blown-in, while cellulose insulation has dense-packed, wet-spray, and loose-fill as well. 

Either type curbs the noise outside your house and comes from recycled materials. Both have health risks to account for. 

In this article, we will factor in the challenges, types, and benefits of both fiberglass and cellulose insulation so you can make an informed choice between two of America's most popular insulation. 

What Is Cellulose Insulation?

Cellulose insulation is one of the most widely used types of insulation in America. Attic specialists refer to it as the "greenest insulation" due to the straightforward garbage-to-attic process it goes through. Manufacturers produce cellulose insulation with recycled newspapers, cardboard, denim, and other recycled paper products. Attic specialists even report seeing bits of currency in some of their cellulose insulation bales. 

Homeowners may choose to install dense-packed cellulose, loose-fill cellulose (or blown-in cellulose), and wet-spray cellulose in their attic. People prefer the installation of cellulose insulation because it is made of sustainable materials, and the minimal processing of turning it into insulation is environment-friendly. Manufacturers produce cellulose in electrically-driven mills, which release little to no greenhouse gases into our atmosphere.  

What Is Fiberglass Insulation?

Fiberglass is an equally green insulation material. Fiberglass insulation owes its fluffy and shiny appearance to spun recycled glass, reinforced plastic, sand, and other recycled materials.

Homeowners may install fiberglass insulation as fiberglass batts, loose-fill fiberglass, or rolled fiberglass insulation. Homeowners favor fiberglass as its uses go beyond the home; you can sometimes see it on boats. Batt insulation is the easiest to install and can be the perfect weekend project for the DIYer. Overall, fiberglass is a superior fire retardant. 

Pros & Cons Of Cellulose

Pros Of Cellulose Attic Insulation

Cons Of Cellulose Attic Insulation

Pros & Cons Of Fiberglass

Pros Of Fiberglass Attic Insulation

Cons Of Fiberglass Attic Insulation


Offhand, cellulose insulation comes off as better insulation than fiberglass because of its higher R-values, higher density, lesser warnings on the packaging, and better impact on the environment and health. But take what some other attic professionals might say with a grain of salt. Some might want only to upsell you with the more expensive cellulose insulation, stressing the higher R-value of cellulose vs. fiberglass and the higher density that cellulose insulation offers. 

Remember that R-values are dependent on your home's climate zone, location, and age. You don’t need the full-blown R-50 value when your attic does not require it. In fact, over insulating your attic opens a whole other world of problems.

Unknowingly compressing insulation loses its R-value, and your attic may not be built for the heavier, denser cellulose insulation. Your home may be more optimal with the lighter fiberglass insulation with an R-38 value.

Blown-in cellulose vs. fiberglass? As for the health risks, you would still need to rely on certified attic specialists in full gear to install both blown-in cellulose and fiberglass insulation. It's best to take advantage of the wealth of knowledge and ready protective equipment they offer. 

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