Cellulose insulation has been around for centuries, with early forms found as far back as 1769 in Thomas Jefferson’s estate. The familiar form we recognize today became popular in the 1920s and truly boomed during the energy crisis of the 1970s and 80s. As the need for energy efficiency grew, so did the popularity of installing this building material in homes. Unlike traditional options, cellulose insulation is made from recycled materials like cardboard and paper, making it an efficient way to save energy while also reducing the carbon footprint.
One of the well-known advantages of this insulation is its ability to prevent emissions, maintain equalized temperatures, and provide superior noise suppression and fire protection. The fibrous state of cellulose allows it to fit compactly and solidly within structures, ensuring sound control, fire resistance, and lower heating and cooling costs. The processes used in manufacturing have improved immensely, making installation easy and helping homeowners make a choice that aligns with the modern era of the green revolution. Unlike other materials, its specific properties allow it to be engineered for fire protection and energy savings, making it a highly used option in the world of construction.
Busting Myths About Cellulose Insulation
Unfortunately, the market is filled with myths about insulation, and the industry is no exception. Many people believe common misconceptions about cellulose insulation, but it’s time to set the record straight. Over the years, experts have rounded up six of the most common claims and debunked them with real facts. These insights have been shared across various building projects, proving that cellulose is a reliable choice. By addressing these concerns, we can provide the right help to those looking for the best insulation solutions.
MYTH 1: Cellulose Insulation Attracts Mold and Mildew
The idea that cellulose insulation attracts mold and mildew is pure nonsense. In reality, boric acid is added during manufacturing as a fire retardant and also works to suppress the growth of these organisms. Since cellulose insulation is made from a common mineral mined from the earth, it naturally resists excessive water intrusion and damage, preventing mold growth on insulation.
Mold rarely grows on cellulose insulation unless there is underlying moisture caused by leaks or poor weathertight construction. A well-installed system reduces the risks of weather-related ruin from wind or water. Unlike other types of insulation, cellulose actively takes on, diffuses, and dissipates moisture to provide long-term moisture management, keeping homes safe and dry.
MYTH 2: Cellulose Insulation Attracts and Harbors Bugs, Roaches, Rats, and Mice
The belief that cellulose insulation attracts and harbors bugs, roaches, rats, and mice is pure nonsense. In reality, borate is added during production, making cellulose insulation highly toxic to insects, small rodents, mold, mildew, and other organisms. Unlike traditional materials that might create a nesting ground, cellulose insulation actively deters pests, ensuring a safer and cleaner home environment.
MYTH 3: Cellulose Insulation Is Harmful to Humans and Unsafe to Touch
The belief that cellulose insulation is harmful to humans is pure nonsense. It is neither toxic nor unsafe to touch. In fact, cellulose insulation contains boric acid, a common mineral added as a fire retardant, which is actually six times less toxic than table salt and is even found in over-the-counter eye drops. The EPA classifies it as a nuisance dust, meaning installers do not need breathing protection, and it is completely safe for household use.
Unlike fiberglass insulation, which can cause skin irritation due to small fibers in the air, cellulose insulation is soft to the touch and does not contain any harmful materials. It does not require protective clothing during installation, making it a safe and reliable choice for homeowners seeking comfort and peace of mind.
MYTH 4: Cellulose Settles Over Time and Loses Its Effectiveness
The claim that cellulose settles over time and loses its effectiveness is pure nonsense. Like all loose-fill and blown insulation, some settling occurs, but manufacturers account for this in their installation formulas. When installed properly, cellulose insulation is warranted to last a lifetime without diminishing performance. Brands like Applegate and Regal ensure that their products maintain their R-value, meaning effectiveness is guaranteed.
The tendency to settle is actually an advantage, as higher-density installation prevents gaps or empty space in the insulated area. The technique of over-packing ensures there is no loss of coverage, effectively busting this common myth. Unlike other materials, cellulose naturally compresses and fits tightly, helping to prevent airflow and improve efficiency over time.
MYTH 5: Cellulose Is Too Heavy to Be Installed Over Fiberglass
The idea that cellulose is too heavy to be installed over existing fiberglass insulation and will cause crushing, reducing its effective R-value is pure nonsense. In reality, the density of cellulose is an advantage rather than a drawback. Research from the Oak Ridge Institute and U.S. Government testing facilities has documented that even a few inches of cellulose insulation can actually re-vitalize older, less-effective insulation.
Unlike fiberglass insulation, which works by trapping airflow, cellulose effectively blocks airflow, reducing energy loss. When blown over the top of lower-density materials, it causes air movement to slow dramatically or even STOP. This results in a quieter, more airtight, and comfortable home that you can enjoy year-round. Rather than being a problem, this method improves effectiveness, proving this myth false.
Also Read: Fiberglass vs Cellulose Insulation: Which Saves More?
MYTH 6 Cellulose Insulation Smells Like Wet Newspapers When It Rains
The claim that cellulose insulation will smell like wet newspapers when it rains is pure nonsense. The only time this could happen is if a roof leaks and keeps insulation constantly wet. However, in such cases, the real problem is not the insulation but a much more serious issue with water damage. Properly installed cellulose insulation does not ever smell badly under normal conditions, as it remains dry and stable unless exposed to excessive moisture for long periods.
MYTH 7: Cellulose Insulation Is Too Heavy and Can Collapse the Ceiling
The idea that cellulose insulation is too heavy and could cause a ceiling collapse due to its increased weight is pure nonsense. In reality, even at R-49, with 13 inches deep, cellulose insulation weighs only 1.8 pounds per square foot. Millions of homes across the USA have cellulose insulation in their attics without any issues. A ceiling would only be at risk if it were improperly installed or had pre-existing damage, making this claim an invalid concern.
MYTH 8: Cellulose Insulation Is More Flammable Than Other Materials
The belief that cellulose insulation is highly flammable because it is made from paper is nonsense. The opposite is actually true. Modern cellulose insulation is treated with fire retardants that significantly improve its fire resistance. Its high-density composition also helps block the passage of air infiltration, which is a major factor in spreading fires. In fact, multi-family commercial applications often require 6 inches of cellulose in a wall to meet the strict fire code requirements set by the fire marshal.
This fire-blocking product is approved under Class 1 flame spread rating and is regulated by the Consumer Product Safety Commission. It has been tested for over 30 years and must meet federal, state, and local fire safety mandates. Even in attics and walls, properly installed cellulose insulation helps increase fire resistance, proving this myth hypocritical. Unlike other insulation materials, it provides reliable consumer protection and meets building code standards, making it a safe and effective choice for any home or commercial unit.
MYTH 9: Cellulose Insulation Contains Asbestos
The claim that cellulose insulation contains asbestos is completely false. Cellulose insulation is a loose-fill insulation that is manufactured without any unhealthy substances like formaldehyde or asbestos. It is not made from textile, fiberglass, mineral wool, or any other fibers, making it a safe and eco-friendly choice for homes and buildings.
MYTH 10: Cellulose Insulation Is a Poor Choice for Older Homes
The idea that cellulose insulation is a poor choice for older homes is far from the truth. In fact, cellulose is great for insulating old homes, whether in attics, walls, floors, or ceilings. Its versatility makes it one of the best loose-fill options, as it is not limited to new construction. It is ideally suited to improve existing attic insulation by adding additional R-value and completely filling any voids or gaps left by other forms of insulation.
MYTH 11: Cellulose Insulation Does Not Air Seal as Well as Foam
The idea that cellulose insulation does not air seal as effectively as foam insulation is a false claim. The theoretical performance of any insulation depends on installation techniques and whether it is installed correctly. Skilled professionals make sure that cellulose insulation is packed tightly inside walls, automatically acting as a top-quality air-sealing barrier. With proper installation, it effectively seals off air and prevents gaps, making it a reliable alternative to foam.
MYTH 12: All Insulation Has the Same R-Value and Works the Same
Many people believe that R-value is all the same, so any insulation material will perform fine, but this is a misunderstanding of industry lingo. It is easy to think that R-value is the same no matter what type of insulation you choose, but it is an important factor to consider when choosing between different types of insulation materials. The way a material performs depends on its ability to reduce heat loss through air infiltration, radiation, and convection. Cellulose insulation offers superior performance because it reduces air infiltration and convection better than many fiber insulation materials with the same R-value.
MYTH 13: Cellulose Insulation Is Expensive
Some people think cellulose insulation is expensive, but the reason behind its costs is often misunderstood. While cellulose wall insulation may cost more to install than fiberglass batts, this is easily made up by the greater savings it provides on energy costs. Additionally, blown-in cellulose and blown-in fiberglass insulations are similarly priced, and cellulose is actually less expensive than foam insulation.
MYTH 14: Cellulose Insulation Contributes to Deforestation
The claim that cellulose insulation uses wood and contributes to deforestation is completely not true. In fact, cellulose insulation does not cause deforestation because it is an environmentally friendly option that is made mostly from recycled content. Unlike traditional materials, cellulose is not made from freshly cut trees but instead comes from recycled paper, with most cellulose insulation containing up to 80 percent recycled material.
Final Thoughts
Cellulose is a safe and reliable product that plays a critical role in delivering better-performing homes. Despite the six myths surrounding it, making the right choice when choosing an insulation material for your project doesn’t have to be a challenging task. With the help of a team of experts, you can get the right facts and guidance throughout the installation process, ensuring the best results for your home.
FAQ
What Are the Negatives of Cellulose Insulation?
While cellulose insulation is a great option, some concerns exist. It can be heavy and may compact underlying materials. In areas of high humidity, it can absorb moisture from rains, which over time may lead to degradation or the need to be replaced. If not properly installed, it can also promote the growth of mold and mildew in the attic.
Do Mice Like Blown-In Cellulose Insulation?
Mice and other rodents are generally not drawn to blown-in cellulose insulation because it is loose and tends to fall in on itself. It is also fire-resistant and not ideal for burrowing or building nests, making it a less attractive option for pests.
What Is the Healthiest Type of Insulation?
The healthiest insulation options are non-toxic and made from natural materials that help in choosing the right insulation for a home while avoiding harmful chemicals. Below are some safe insulation types:
- Cellulose – Made from recycled newspaper, an eco-friendly and natural option.
- Wool (Sheep’s Wool & Mineral Wool) – Comes from melted rock or blast furnace slag, offering fire resistance.
- Hemp & Cotton – Derived from plant-based fibers or post-industrial scrap denim.
- Cork – A safe, natural option with great insulating properties.
Can Mold Grow on Cellulose Insulation?
Cellulose insulation itself is treated to be mold-resistant, but the surrounding structure may not be. Understanding how and why mold is likely to occur can help prevent serious structural damage. Given the risks, taking swift action is imperative if you suspect that the insulation has become wet.