What Is Cellulose Insulation? Pros and Cons

Suppose you’re looking to decrease your home energy bill or increase your home’s value before putting it on the market. In that case, you might consider replacing your home’s existing insulation or installing an insulation product for the first time.

You have numerous options to consider when choosing the perfect insulation type for your home—one of which is cellulose. But, what is cellulose insulation? Is it the best choice for your home’s age, your budget, and the longevity you’re seeking?

In this guide, our expert team will break down everything you need to know about cellulose insulation. We’ll cover some basic details about attic insulation, what cellulose is made from, the different types available, the installation process, R-value information, and pros and cons. We’ll also touch on the other options you’re likely to encounter in your search for the best product.

How Does Insulation Work?

Insulation products reduce one or more of the three different types of heat flow:¹

Conduction – Conductive heat flows through solid materials. A hot cup of coffee transfers heat from the outside of the cup and into your hand, for example.
Convection – Convection describes the way heat moves through liquids and gasses. When you turn on your furnace in the winter, hot air flows through your vents into the various rooms in your home via convective heat flow.
Radiation – Radiant heat moves in a straight line until a solid object in its path absorbs the heat energy—like rays from the sun warming your skin.

Insulation provides resistance against heat flow—it prevents heat from escaping into your attic in the winter and hot air in the attic from infiltrating your air-conditioned spaces in the summer.

All About Cellulose

Cellulose insulation is one of the many products that provide convective and conductive heat resistance in your home. Let’s break down everything you need to know about cellulose.

Cellulose Insulation Materials

Cellulose is made from paper fibers that have been chemically treated to:²

Help the fibers stick together
Prevent compression and settling
Deter pests
Increase heat resistance

In most cases, cellulose fiber is made from recycled paper materials—newsprint is the most common.

While you might be visualizing shreds of paper, cellulose insulation has more of a pulpy texture since it’s made from very small paper particles. So, installing it can be a dusty proposition.

But, if laid at the appropriate thickness, the small paper fibers in cellulose insulation can stick together and pack closely enough to provide additional heat resistance. And, since it’s made from recycled paper, cellulose is a relatively sustainable insulation material.

Cellulose Insulation Types

There are a few different types of insulation products (which we’ll explore in more detail in a later section), but cellulose insulation only comes in one form—blown-in insulation, also called loose fill insulation.³

What is blown-in insulation?

During installation, insulation professionals use specialized blower equipment to “spray” insulation fibers onto a surface or into a space—the areas between the joists on your attic floor, for example. Although the insulation is being sprayed, blown-in insulation vs spray foam is a much different process.
Instead of scattering it by hand or rolling it out onto a surface, blowing in the product allows installers to apply the product at an adequate thickness and cover surface areas completely—even nooks and crannies.
Blown-in insulation isn’t always made from cellulose. Fiberglass and mineral wool insulation products can also be blown-in.

Keep in mind that blown-in insulation isn’t a perfect solution. It’s still susceptible to wear and tear, settling, and compression:

Normal wear and tear – All insulation products naturally degrade over time—no matter how they were installed or what they’re made from. Like most other building materials, they should be replaced when their condition no longer makes them effective.
Settling – Insulation materials settle over time, whether they’re blown-in, sprayed, or rolled out. Gravity causes the spaces between insulation particles to decrease as the particles on top slowly droop. While it’s completely normal, it can sometimes decrease the R-value of an insulation product (we’ll discuss R-values in an upcoming section).
Compression – Compression is most common in attic spaces. Whenever you step on your insulation or place an object on top (like a box of holiday lights or winter coats), the insulation material compresses under pressure. Like settling, this can decrease the R-value of your insulation.

Installing Cellulose Insulation

How do insulation professionals install cellulose insulation?

After donning their protective gear, they remove all the old insulation (if applicable), storage boxes, pest debris, and dirt from an attic space to prepare for installation.
They create a clear path from the attic hatch (or the installation access point) to the main door they’ll use for moving equipment, workers, and materials.
They transport the necessary equipment to the installation access point.
They use a specialized blower to distribute cellulose in an even, consistent layer in an attic space, between stories, behind walls, or underneath the ground floor of a space.
They review the entire insulated area, ensuring that every inch of the surface has been covered with cellulose and that it’s the right thickness throughout.

It’s important to note that, since cellulose requires specialized equipment to install, it’s difficult to DIY. In addition, since cellulose insulation creates significant dust during installation and it’s chemically treated with a fire retardant chemical, installers must wear masks, gloves, and other critical safety equipment during the process.

Cellulose Insulation R-Value

R-value is a unit of measurement that describes how effectively a material resists heat flow.⁴ To calculate R-value, insulation product manufacturers use the following formula:

Temperature (°F) x hours of exposure x square feet/BTU (British Thermal Units) = R-value

A higher R-value generally indicates higher resistance to heat transfer. But, it’s important to note that R-value is not directly proportional to insulation thickness—thicker layers don’t necessarily feature higher R-values.

In addition, cellulose insulation R value isn’t the only factor to consider when choosing an insulation product. Before selecting a type and material, think about:

The age of your home – Insulation will decrease your home energy bill, but it also works in tandem with other systems to prevent heat transfer. If you live in an older home with an aging HVAC system, damaged or degraded building materials, or roof leaks, the R-value of your insulation product will matter less than the general disrepair of your home.
Your budget – You might not be able to afford the insulation product with the highest R-value. You should choose the best insulation product in your price range and that’s appropriate for the application.
Product longevity – Insulation is exposed to normal wear and tear, but different products respond differently to typical aging. Even products with high R-values can lose R-value as they degrade—some more quickly than others.
Placement and applications – If you install a high R-value insulation product in your attic and then compress it all with storage boxes, you may have defeated the purpose of installing a high-resistance product. Choose the option that works best for your specific applications.

Advantages of Cellulose

Cellulose insulation certainly has advantages:

It’s a dense product, so it generally provides high heat resistance.
Blown-in insulation is useful in most application areas.
It’s sustainably made from recycled material and organic matter.

But, do these advantages outweigh the disadvantages?

Disadvantages of Cellulose

Cellulose is far from a perfect product:

It produces significant dust during installation, which can create a mess and possibly be a hazard for installers, without the proper equipment.
It requires specialized equipment to install, so it’s less DIY-friendly than its batt insulation counterparts.
It’s prone to settling and compression, which can decrease its R-value.
Cellulose vs fiberglass batt insulation (one of the most widely-used insulation products on the market) is more expensive.

How Does Cellulose Compare to Other Insulation Types?

Cellulose might not be the best product choice for your home. But, what are your other options?

There are two insulation types available for home applications:

Blown-in insulation
Batt (also called blanket or roll) insulation

Batt insulation is sold in pre-cut rolls that installers place between floor joists, trusses, and wall studs. It comes in standardized widths for simple installation.

Cellulose is only one of a few insulation materials on the market today:

Fiberglass insulation is the most commonly used material for residential insulation applications
Spray foam insulation is similar to blown-in insulation, but it uses a liquid foam product
Mineral wool insulation is becoming less common, but it’s available in batts or loose-fill

Each of these insulation types and materials has its own set of advantages and disadvantages. Still, there’s a reason why fiberglass batts are used so widely in residential applications—it’s cost-effective, long-lasting, and time-tested.

For many applications, it’s a better choice than cellulose insulation:

It doesn’t create dust during installation.
It’s less prone to mold and mildew growth than cellulose.
It’s available in both loose-fill and batt types.
It’s generally less expensive than cellulose.

But, as we noted above, the other systems in your home are just as important as your insulation for reducing your energy costs and use—make sure your HVAC system, your exterior cladding components, and interior building materials are all ship-shaped to optimize your home energy use.

Insulate Your Home with Confidence: Choose Attic Construction

Cellulose insulation might be a good choice for your home—but, it’s not the only choice.

So, how do you choose the best possible insulation product? Consult with a team of experts like those at Attic Construction. We’ve been providing attic services—like cleaning, insulation removal and replacement, and rodent-proofing—since 2011, and we’re the brand of choice for attic cleaning in Orange County.

Our commitments to quality work and customer service have followed us for over a decade, and we’re just getting started. We can’t wait to help you make your home the best it can be.

Sources:

US Department of Energy. Insulation. https://www.energy.gov/energysaver/insulation
HomeAdvisor. Comparing the Pros and Cons of Cellulose and Fiberglass Insulation. https://www.homeadvisor.com/r/cellulose-vs-fiberglass-insulation/
US Department of Energy. Types of Insulation. https://www.energy.gov/energysaver/types-insulation
ScienceDirect. R-Value. https://www.sciencedirect.com/topics/engineering/r-value