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Is Cellulose Insulation Safe? Yes! Here’s Why

Blown-in cellulose is often seen as an economical alternative to fiberglass and spray foam insulation, with the added benefit of environmental sustainability. 

However, customers in Northeast Pennsylvania often question whether cellulose insulation is strong enough to keep their homes warm during the winter or safe against fires.

While cellulose insulation boasts a high R-value and is considered very safe, some popular myths still persist about it in the insulation world. 

This article will tackle these myths and more to answer the age-old question: is cellulose insulation safe?

What Is Blown-In Cellulose?

Blown-in cellulose insulation is made from recycled paper fibers that are treated with fire retardants. These fibers are finely shredded and treated with borates and other materials to resist insects and mold. 

The result is a dense, fluffy material that effectively traps air and provides excellent insulation for homes.

Like blown-in fiberglass, cellulose can be installed in tight cavities, including walls and attics. For this reason, cellulose is often one of the best types of insulation for walls and attics.  

How Safe Is Blown-In Cellulose?

Cellulose consists of organic paper and cardboard materials that are recycled for sustainability. To prevent these materials from catching fire, fire retardants are added to cellulose to make them flame-resistant. 

Additionally, borates are added, which makes cellulose resistant to insects and mold. In summary, blown-in cellulose is a safe material to insulate your home. 

How Is Blown-In Cellulose Installed?

Cellulose insulation is typically blown in with a specialized machine that a professional operates. For existing homes, we will drill a small hole in the exterior wall, underneath the siding, to provide ready access to the wall cavity. 

Once inside, the machine will fill the cavity with a dense bundle of cellulose, providing a thermal barrier between the outside and inside. 

Thanks to the product’s density, it can also be installed into attic rafters without fear of the insulation material falling out or coming loose. 

Benefits of Blown-In Cellulose

    • Excellent Thermal Performance: On average, cellulose provides an R-value of R-3.5 per inch, making it more efficient than some forms of fiberglass batt or open-cell spray foam. 
    • Sound Dampening: The dense fibers of cellulose insulation also provide excellent soundproofing, reducing noise transmission between rooms.
    • Environmentally Friendly: Made from recycled materials, cellulose insulation is a sustainable choice that helps reduce landfill waste and energy consumption.
    • Resistant to Insects and Mold: Cellulose is highly moisture-resistant and treated with borates to fend off insects and mold. Cellulose is also good at protecting residents from seasonal allergies outside.
  • Cost-Effective: Compared to products like spray foam or fiberglass, cellulose is often viewed as a more affordable option. 

Common Misconceptions of Blown-In Cellulose:

Despite its safety and numerous benefits, blown-in cellulose insulation is sometimes subject to misconceptions. This has hindered its popularity despite being completely safe and practical. Here are a few common myths debunked:

  • Mold Growth: Boric acid is added to cellulose mixtures to prevent mold growth. Boric acid is considered an organic compound that also fights off insects. 
  • Pest Magnet: Since cellulose is made from organic and recycled materials, many people think this will attract bugs. However, borates are added to help prevent insects. 
  • Settling and Compression: Like any insulation material, cellulose insulation may settle slightly over time, but manufacturers calculate this into their formula. Therefore, the R-value you think you’re getting from cellulose is actually a conservative estimate of its actual thermal efficiency. 
  • Health Concerns: Some people express concerns about airborne particles during installation. However, installers typically wear protective gear, and the settling process quickly reduces any airborne particles to negligible levels. Once installed, cellulose insulation poses no health risks to occupants.


Blown-in cellulose insulation is a safe and affordable alternative to fiberglass and spray foam insulation

Made from environmentally sustainable materials, it’s also great for the environment and perfect for old or existing homes.

Be sure to partner with a professional offering the best value for your investment when installing cellulose insulation. 

This could be the difference between long-lasting and efficient insulation and insulation prone to chronic issues. 

FAQs: Is Cellulose Insulation Safe?

Is cellulose insulation safe for homes with pets?

Yes, cellulose insulation is safe for homes with pets. The fire retardants and borates used in cellulose insulation are non-toxic and pose no harm to pets.

Can blown-in cellulose insulation be installed within existing walls?

Yes, blown-in cellulose insulation can be installed in existing walls by drilling small holes and blowing the insulation into the cavities. In fact, blown-in insulation is designed for that exact purpose. 

How long does blown-in cellulose insulation last?

When properly installed and maintained, blown-in cellulose insulation can last for the home’s life.

Is cellulose insulation environmentally friendly?

Yes, cellulose insulation is environmentally friendly as it is made from recycled materials and can be recycled at the end of its lifespan.