Fiberglass vs Cellulose Blown Insulation – Which is Better for Your Home?

Cellulose vs Fiberglass, Images /

Fiberglass vs cellulose blown insulation – which is better for your home?

When it comes to insulation, fiberglass and cellulose have been around for a long time. They’re still popular insulation types used in homes across the country today.

How they work is the same: they’re both loose-fill insulation types that keep heat from escaping through the wall of your home.

They also do a great job of reducing noise transfer, moisture absorption, and air leakage around your home. So which type of insulation is better?

That depends on your space, needs, and budget. Let’s find out more about fiberglass insulation vs cellulose insulation and get an idea of how these insulation types differ.

Cellulose vs Fiberglass Insulation

  • cellulose blown insulation is made from recycled newspaper and other paper products. It is more cost-effective than fiberglass insulation, but it may not be as effective at stopping heat loss.
  • fiberglass insulation is made of glass fiber, which is a type of wood pulp. Fiberglass insulation is more expensive than cellulose blown insulation, but it has a higher R-value and can last for many years with proper care.
  • cellulose blown insulation can help reduce greenhouse gas emissions, but fiberglass insulation provides greater protection against the elements and has no harmful impact on the environment.
  • if you are looking for an environmentally friendly option, fiberglass blown insulation may be a better choice for you. Besides being cost-effective and durable, fiberglass insulation offers an even balance between efficiency and environmental friendliness.

What is Fiberglass Insulation?

What is Fiberglass Insulation?
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Fiberglass insulation is a kind of insulation that creates numerous air pockets to allow convective and conductive heat flow throughout your home.

During the building process, this kind of insulation is used on unfinished floors, ceilings, and walls. Between joists, beams, or studs, the contractor puts the fiberglass insulation.

Batts, rolls, boards, and loose-fill fiberglass insulation are all options. Wall-to-wall or from one end of the ceiling frame to the other, fiberglass insulation rolls are generally large and may be used. Fiberglass batts, on the other hand, are generally smaller and may be put in place as a do-it-yourself project.

Note: The vitreous melt is fashioned into fibers using heat to produce fiberglass insulation.

Insulating hard-to-reach places such as around wiring in the wall cavity is typically accomplished with blown-in fiberglass in loose-fill form. Small insulation gaps may result in inefficient thermal performance, so blown-in fiberglass insulation is crucial.

Over drywall, concrete, and wood, fiberglass boards are simple to install. Because of their simplicity of insulation, fiberglass insulation boards are favored among do-it-yourselfers for ceiling and wall insulation.

Fiberglass Batts

Fiberglass insulation is a type of thermal insulation that uses glass batts. Batts made from fiberglass are usually loose-fill insulation, which means they contain fiberglass rather than cellulose as the main component.

These batts are generally thinner and lighter than cellulose-blown insulation and are easy to install. They have a lifespan of up to 30 years, making them an affordable and sustainable choice for home insulation.

While fiberglass insulation is fire-resistant compared to cellulose blown insulation, it is still a good choice for homes that are not at risk of fire. Overall, fiberglass insulation is a cost-effective and sustainable choice for homeowners looking to improve the energy efficiency and comfort of their homes.

Loose-fill Fiberglass

Loose-fill fiberglass is a type of insulation made from recycled newspaper and other cellulose materials.

This type of insulation is typically a loose-fill insulation, which means it fills the cavities of a wall or attic with loose fibers instead of batt or batts.

Loose-fill insulation is a sustainable and cost-effective choice for homeowners who are looking for an energy-efficient and durable solution for their home insulation needs.

This type of insulation offers good thermal performance, moisture barrier, and airtightness, making it a good choice for homes with high moisture levels or frequent moisture leaks.

In addition to its insulation properties, loose-fill fiberglass is also practically airtight and moisture-resistant, which makes it the best choice for homes with high moisture levels or frequent moisture leaks.

Pros and Cons of Fiberglass

The fact that fiberglass has so many benefits and just a few drawbacks is one of the reasons it is such a popular option for both homeowners and attic experts.

Cellulose vs Fiberglass Insulation Pros and Cons
Fiberglass Insulation ProsFiberglass Insulation Cons
It’s cost-effective and cheap to use.When it’s wet, it doesn’t work properly, and it takes a long time to dry it properly.
By 40%, it helps to cut down on your energy costs.Health risks may result from improper self-installation and handling.
In ideal conditions, it may last up to 100 years.At high temperatures and in severe cold, it loses its R-value.
Lower risk of it catching fire or developing moisture-related problemsWhen squeezed or packed tightly, it loses its R-value.
Excellent noise insulation
R-value between 2.2 and 4.3
Sagging fiberglass bats are less likely to settle.
Cellulose Insulation ProsCellulose Insulation Cons
Fiberglass has a 75% cheaper cost.To be pest-repellent, it must first be chemically treated.
It’s easy to put together and comes in tiny pieces.A fire-risky substance is flammable.
R-value ranges between 3.2 and 3.5After installation, effectiveness is reduced.
When compressed, the R-value is lost less.When wet, mold can grow quickly, making it ineffective.
Even in extreme cold, it maintains R-value.Produces a lot of dust, creating a mess
Advantages of fiberglass include:
  • Cost-Effective and Energy Saver – Fiberglass is a low-cost, highly effective insulator, not only making it a cost-effective material but also saving you money in the long run by reducing your energy bill by 40%.
  • Long-Lasting – In ideal conditions, fiberglass may last more than 100 years. It doesn’t shrink over time, unlike other insulation materials.
  • Non-Flammable & Moisture-Resistant – Despite the fact that fiberglass has a cotton-like appearance, it is mostly made up of glass, which minimizes the risk of it catching fire or developing moisture-related issues in humid weather.
  • Noise Insulation – Not only does fiberglass protect your home against weather, but it also protects you against unwanted noise. Fibreglass insulation may help make your home a quieter and more peaceful place whether you live in a congested neighborhood with heavy traffic or have a loud generator outside.
Disadvantages of fiberglass include:
  • Ineffective When Wet – The insulation will not be able to work effectively until it has been professionally dried if your fiberglass gets significantly wet due to a leak in your attic.
  • Self-Installation Can Be Dangerous – Fiberglass is dangerous to touch because it is made up of tiny glass particles, and handling it without taking care can result in health issues like rashes or lung damage. When installing fiberglass insulation, it’s always best to seek the advice of an expert or insulation contractor.

What is Cellulose Insulation?

What is Cellulose Insulation?
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Cellulose insulation is a form of recycled paper product that is used in buildings. Blown-in cellulose insulation is made from shredded and mixed waste paper products like discarded cardboard boxes and old newspapers.

Fire retardants include boric acid, ammonium sulfate, and borax. Because they pose the least danger, these substances are permitted for use. 85% of cellulose insulation is made up of recycled paper, while the remaining 15% is flame retardants.

Loose-fill cellulose insulation, dense-packed cellulose insulation, and wet-applied spray cellulose insulation are the three types of cellulose insulations available. Wet-applied spray cellulose insulation is only installed in new buildings prior to drywall installation, while the first two may be utilized on new and old buildings.

You’ll have to rip a piece of the exterior siding off and drill 3-inch holes into each stud cavity in order to install blown-in cellulose insulation in existing structures. Before plugging the openings, you should then blow the cellulose filling into the space using a unique filler tube. Lastly, replace the exterior siding.

Cellulose insulation increases soundproofness and thermal insulation in your home. In addition, it prevents pests and mold from damaging your drywall walls and ceilings, thanks to flame retardants.

Old Home Installation (Blown Dry)

Cellulose insulation is made from cellulose, a plant-based material. It is a type of blown insulation that offers high R-value and cost-effective insulation. Cellulose insulation can be installed in new or old homes, but the installer may require special care during installation.

The benefits of cellulose insulation make it a good choice for homes seeking energy efficiency and thermal comfort. It can be installed quickly and easily, making it ideal for home renovations and energy-efficient retrofits. Overall, cellulose insulation offers homeowners affordable and effective insulation that can help save on energy costs and reduce greenhouse gas emissions.

New Home Installation

  • Damp-sprayed – The starch in the cellulose is activated by adding moisture to the tip of an insulation spray nozzle. Then, it is sprayed inside your home’s empty spaces.
  • Dry-netting – Stapled across the openings in the structure are a net full of dry cellulose.

The kind of home you have and the tools at your disposal will determine the optimum method of cellulose insulation installation.

Pros and Cons of Cellulose

The advantages of using paper-based insulation outweigh the disadvantages, but there are a few.

Advantages of cellulose include:
  • Low-price – Because it is made of paper, cellulose is even more cost-effective than fiberglass at around 75% of the cost.
  • Easy Installation – Cellulose is available in little pieces and may be installed in a variety of ways, making it ideal for most homes but quite difficult.
Disadvantages of fiberglass include:
  • Not Pest Repellant – Cellulose is commonly treated with chemicals such as boric acid, which claim to repel rats and insects. However, it is not naturally pest repellant. Boric acid does little to prevent rats from entering your home, exposing it to a possible infestation in reality.
  • Naturally Flammable – To enhance cellulose’s flame resistance, it is also treated with chemicals, although paper resists burning rather than non-flammable insulation materials.
  • Settles After Installation – After installation, cellulose insulation tends to settle by several inches, reducing its effectiveness.
  • Mold Grows When Wet – When wet, cellulose is just like fiberglass, but it’s also dangerous, unlike fiberglass. Mold and mildews grow well on the cellulose paper base, which is acidic when exposed to water, and boric acid used to treat it may become corrosive.
  • Excess Dust – Since cellulose is mostly composed of finely pulverized paper, it produces a lot of dust when being put in place, making it difficult to clean up and posing a safety concern for those putting it in.

R-Value: The Role of Thermal Resistance

When comparing various forms of insulation, R-value is one of the most important factors to consider. R-value represents a material’s capacity to keep warm locations warm and cold locations cold, or in other words, its thermal performance.

By insulating your house more effectively and saving you money on energy, materials with a higher R-value will help you keep a more constant temperature indoors.

The R-values of different insulation materials differ depending on how they deal with heat flow. Depending on the density of the material, fiberglass has an R-value of 2.2 to 4.3, whereas cellulose has an R-value of 3.2 to 3.5.

As a result, cellulose insulation has a somewhat higher average R-value than fiberglass, but high-quality fiberglass is more thermal resistance than high-quality cellulose.

Fiberglass vs. Cellulose Blown Insulation – Key Differences

Moisture damage can affect both fiberglass and cellulose insulations. They may be utilized to offer thermal sealing, and they may be combined with diverse forms of insulation material.

However, despite the several differences between fiberglass and cellulose, these few similarities can’t match.

The cost, eco-friendliness, insulation capacity, and lifespan of fiberglass and cellulose-blown insulation are the key distinctions.

Fiberglass vs. Cellulose Blown Insulation

Insulation capacity

Blown-in cellulose has an R-value of 3.2 to 3.8 inches, whereas loose-fill fiberglass has an R-value of 2.2 to 2.7 inches per inch. As a result, cellulose insulation is superior to fiberglass.

The R-Value – a indication of the conductive heat flow resistance of a material – is used to calculate the material’s insulation capacity.

When tightly packed or exposed to extremely cold temperatures, fiberglass insulation loses some of its R-value. Cellulose insulation, on the other hand, retains its R-value even when it is compressed to minimum levels.


Cellulose insulation has a typical lifespan of 20 to 30 years. Insulation made of fiberglass has a superior lifespan than cellulose.

As time goes on, cellulose insulation becomes packed and sags, losing its R-value and creating space in the parts where it has sagged. These vents allow heated or cooled air to enter the home, wasting energy.

In contrast, over its 80-100-year lifespan, fiberglass insulation maintains its shape and form. As a result, fiberglass insulation products are often provided with a guarantee of life.


Cellulose insulation is sometimes less costly than fiberglass. Fiberglass insulation costs $0.91 per square foot on average, while blown-in cellulose ranges from $0.90 to $1.50 per square foot.

Cellulose insulation, which is less costly than blown-in fiberglass insulation, may still be found. Batts, on the other hand, are more cost-effective and cost as little as $0.30 per square foot for fiberglass insulation.


Cellulose is a more eco-friendly option than fiberglass. It’s biodegradable and made of recycled paper material. Because it creates fewer thermal bridges, cellulose is better at regulating airflow and saving energy.

Fiberglass insulation, on the other hand, does not decompose since it is made of molten glass particles. In tight areas, you may obtain denser variations that are more efficient.

Health and safety

Since it is made of recycled paper content, blown-in cellulose insulation is deemed safer than fiberglass insulation.

Furthermore, cellulose insulation treatments do not contain harmful chemicals. To avoid inhaling paper dust, you’ll need to wear a respirator mask.

Fiberglass insulation, on the other hand, is known to cause breathing difficulty during installation. When installing fiberglass insulation, it’s vital to wear a dust mask. It also causes skin irritation, which is even worse.


Fiberglass rolls, batts, or loose-fill fiberglass are available for purchase. Loose-fill cellulose insulation is the only option.

On both sides, this discrepancy has benefits and drawbacks. You can infill the hard-to-reach spaces with loose-fill fiberglass to save money by installing fiberglass batts, which are more cost-effective.

Installing fiberglass batts, on the other hand, may be challenging. Gaps might occur where the batts have come apart, become misshapen, or ripped. While blown-in cellulose might be more expensive, it is simple to put in place, and it can fit into any room or cavity.

When it comes to blown fiberglass and blown cellulose insulation, there are a few distinctions to keep in mind.

Blown fiberglass insulationBlown cellulose insulation
$0.91 per square foot is the average cost of fiberglass blown insulation.Cellulose insulation installed inside the walls costs $0.90 to $1.50 per square foot.
Since it is made of glass, fiberglass does not biodegrade.Because it is made of paper, cellulose is biodegradable.
R-value of R-2.2 to 2.7 per inchR-value of R-3.2 to 3.8 per inch
Heat flow resistance is lowered in this material.It has superior heat flow resistance.
80-100 year lifespanShorter lifespan of 20-30 years
Nose and throat irritation are possible side effects of inhalation, while skin irritation is possible with physical contact.Non-toxic to humans
Fiberglass batts go well with it.If mixed with fiberglass batts, it may reduce the R-value.

Should I Choose Fiberglass or Cellulose Insulation?

While both fiberglass and cellulose insulation have their benefits and may be suitable in various situations, fiberglass has significantly more benefits as compared to its drawbacks.

Fiberglass insulation is a cost-effective and straightforward way to insulate your home that protects you against many of the dangers associated with poor insulation materials.

As a result, we recommend fiberglass for high-quality insulation that will last over cellulose. Furthermore, read our recent blog to learn the distinction between these two forms of insulation and make the best informed decision for your home if you haven’t considered blow in vs spray foam.

Frequently Asked Questions

Can you mix cellulose and fiberglass insulation?

A technique known as capping involves combining fiberglass and cellulose insulation. Capping allows you to reuse old insulation rather than having to remove it and replace it with new insulation.

It is difficult and labor-intensive to remove old fiberglass batts from the wall paneling. It is more practical and cost-effective to blow cellulose insulation onto top of the existing fiberglass insulation batts/rolls.

Capping, on the other hand, has a downsides; cellulose particles may penetrate air caverns inside fiberglass insulation, lowering its R-value.

What are the benefits of fiberglass blown insulation?

There are a few benefits of fiberglass blown insulation when compared to cellulose blown insulation:

  • Fiberglass blown insulation is less expensive than cellulose blown insulation.
  • Fiberglass blown insulation is more resistant to moisture and pests.
  • There are a number of Benefits to using fiberglass blown insulation in your home, including better energy efficiency, improved comfort, and reduced home energy bills.

What are the benefits of cellulose blown insulation?

When it comes to insulation, cellulose blown insulation is a popular choice because of its environmentally friendly properties.

This insulation uses cellulose to create a thermal barrier, which is considered to be more energy-efficient than other types of insulation.

Additionally, cellulose blown insulation can reduce noise levels in your home and inhibit the infiltration of moisture.

When choosing cellulose blown insulation for your home, it is important to consult with a qualified contractor.

There are a variety of cellulose blown insulation products available on the market, so make sure to choose the one that best suits your needs and budget.

Some popular brands of cellulose blown insulation include Battenfeld, Ecobond, and Fibertex.

Which is better for my home – fiberglass blown insulation or cellulose blown insulation?

Your needs, location, and budget will all factor into your decision.

Nonetheless, if you reside in a cold area and prefer blown-in cellulose insulation than fiberglass, I suggest that you choose it instead of fiberglass insulation because it performs colder weather better.

On the other hand, if you want a long-term insulation solution, fiberglass is the better option since it can last up to 100 years..


The fiberglass insulation material is the most widely-used type of insulation material in the United States. It offers better moisture-resistance and helps to keep the structure of your home more stable against changes in the weather. However, cellulose insulation material is gaining popularity due to its environmental benefits.

For example, cellulose insulation material can be recycled and can be cut with a weed-whacker for easy disposal. It also doesn’t degrade or weaken with age, and it doesn’t require any special handling or preparation before application.

A homeowner could find it helpful to research online for fiberglass insulation material as well as cellulose insulation material installation cost, and comparing the benefits of each. Encompass yourself in the knowledge and save yourself from unwanted surprises!

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