7 Things Homeowners Should Know About Cellulose Insulation

Insulation is a key component for home heating and cooling efficiency, which is why it is commonly installed in the walls and attics of most new homes and regularly replaced in existing homes. Blown-in insulation is a popular option because it fills the crevices and gaps, reducing drafts and improving home energy efficiency, though some DIYers may add loose fill insulation to increase the R-value of the existing insulation or deal with irregularly shaped areas of the home. 

Cellulose attic insulation is one of the most frequently installed types of blown-in insulation, though you can also install cellulose insulation in walls to slow the transfer of heat into and out of the home. The R-value of cellulose insulation tends to be higher than comparable materials, and it’s often less expensive as well. Because of this, cellulose insulation has been growing in popularity. Use this informative guide to learn more about cellulose insulation and the benefits it can bring to your home. 

1. Cellulose insulation is primarily made of recycled paper products.

One of the best features of cellulose insulation is that it’s a green material that is made primarily from 80 to 85 percent recycled paper products, according to the U.S. Department of Energy. Most of this percentage is made up of old newsprint and similar paper materials that are first reduced to small pieces before being fiberized to create one of the best attic insulation options available.

To help mitigate cellulose insulation dangers, the fiberized material is then treated with fire-resistant and insect-resistant mineral borate, which can sometimes be blended with ammonium sulfate for a more affordable finished product. This combination creates an energy-efficient insulation that can be blown into attics and walls for quality insulation that can last for decades.

2. Cellulose insulation is typically used in attics and walls of new and existing homes.

When you are considering different types of insulation for the home, it’s important to know where each type of insulation is best suited for use. In most cases, cellulose insulation is installed in the attics and walls of new homes, though it can also be blown into finished walls without needing to remove the drywall, making it a fast, effective way to add to existing insulation or to replace old insulation materials.

The main reason for installing cellulose insulation in these areas of the home is because of the affordable cellulose insulation cost, high R-value, and various insulation methods that make it easier for professionals to install. Additionally, the fire-resistant and pest-resistant nature of the material helps to protect the home and deter unwanted invaders. 

3. Cellulose insulation is most commonly installed by being blown in.

Cellulose insulation can be installed using the loose-fill method in which the installer or DIYer simply blows the insulation into an open attic using a blowing machine. This method is effective for fast and easy installations in open areas, but the loose-fill cellulose does not have the same R-value as dense-fill cellulose.

For dense-fill installation you need to use a specialized cellulose insulation blower with a smaller hose that results in a much higher density of insulation with minimal air pockets. This type of blown-in insulation is commonly used to fill wall cavities and enclosed finished spaces, though it can also be installed behind netting that is stapled over building cavities. 

Similarly, some installers may use the damp spraying method to install cellulose insulation by adding a small amount of moisture to the spray nozzle tip, which activates the natural starches in cellulose, causing it to adhere to the inside of the cavity.

4. Cellulose is an efficient, affordable alternative to other types of insulation.

When cellulose is contrasted with other types of insulation, it’s common to see one-for-one comparisons between cellulose vs. fiberglass insulation because both materials are affordable and widely used in the residential building industry. Similarly, the R-value, cost, and installation difficulty of blown-in insulation vs. spray-foam insulation are often compared when homeowners are trying to decide on the best insulating material to add to their home. 

During these comparisons, most homeowners come to find that cellulose is an energy-efficient material with low environmental impact that is designed to be both fire-resistant and pest-resistant. Additionally, cellulose can be injected directly into finished walls or blown over existing fiberglass batts, and it has a relatively affordable cost that makes it a great choice for homeowners on a budget. 

5. Cellulose insulation has an R-value of R-3.2 to R-3.8 per inch.

Deciding between several different types of insulation can be difficult, especially if you don’t know what R-value is or how it impacts the quality of the insulation. R-value is essentially the measurement of how much heat resistance the material has per inch of depth. With this in mind, you can compare the average cellulose insulation R-value, which ranges from R-3.2 to R-3.8 per inch to other common insulation materials to help decide on the right insulation for your home.

Fiberglass insulation is a popular choice for residential properties; however, while it does have an affordable cost, the average R-value is just R-2.2 to R-2.9 per inch. Mineral wool insulation is a better choice, ranging from R-3.0 to R-3.3 per inch, while spray-foam insulation can vary depending on the specific type used, with a minimum average R-value of R-3.5 per inch and a maximum average R-value of R-6.5 per inch.

6. Blown-in cellulose insulation can be hazardous if not installed properly.

While there are many great benefits to installing cellulose insulation, it’s important not to overlook the potential hazards of this material, especially if it is not installed correctly. Since cellulose insulation is treated with fire-resistant and pest-resistant compounds, airborne fibers can cause respiratory problems, eye irritation, or skin irritation, which is why installers need to wear appropriate protective equipment during the installation process.

Also, if the insulation is installed over vents or too close to sources of ignition, there is an increased risk of the cellulose insulation catching fire, despite the fire-resistant treatment. This is especially true if the insulation is densely packed around electrical components and flammable materials. 

Additionally, since cellulose is hygroscopic, it soaks up and holds water, so if there are any leaks that go undetected, the cellulose insulation will soak up the excess water, causing it to sag or become compressed within the framing cavities. Exposure to water also has the potential to make the chemical components of cellulose insulation corrosive, which can lead to extensive damages in the attic and inside the walls. 

7. Cellulose insulation is naturally biodegradable.

After installing cellulose insulation, you can expect it to last for 20 to 30 years before it will need to be replaced. The old cellulose insulation will begin to naturally decompose as it reaches the end of this two to three decade lifespan, whereas other insulating materials, like fiberglass or foam, will continue to persist in landfills for significantly longer.

However, it’s important to keep in mind that cellulose insulation is treated with fire-resistant and pest-resistant compounds. The biodegradability of cellulose insulation depends on the specific type of treatment, though most cellulose material uses boric acid as a fire retardant, which is considered to be biodegradable and can even help with healthy plant growth. For this reason, cellulose insulation is widely considered a green material that is eco-friendly and naturally biodegradable, reducing your carbon footprint and household waste.