Pros and Cons of Cellulose Insulation (What to Expect)

Most modern homes these days have insulated walls and ceilings. It is a good investment if you want to keep your walls undamaged and your rooms cool. Cellulose happens to be a very popular choice for insulation due to its many positive features, such as biodegradability and resistance to mold.

Moreover, cellulose insulation has been a primary medium of insulation for the green building movement to build more eco-friendly homes as it is made up mostly of recycled materials.

However, like most things in this world, cellulose has its own set of pros and cons. If you are considering insulating your walls with cellulose then it will serve you well to give this a read.

But before we dive into the pros and cons of wall insulation with cellulose, let us first familiarize you with exactly what cellulose is.

What is cellulose?

It is a type of insulation that comes in dry and wet types. Cellulose is made from recycled paper and denim, which makes it very convenient for eco-friendly building projects. The “wet” type of cellulose is not exactly liquid but is more molten and damp when it is applied to the wall cavity by spraying.

Pros and cons of Cellulose Insulation

Pros and Cons of Cellulose Insulation

Apart from the two primary classifications, cellulose also has some other classifications such as blown-in cellulose insulation, loose-fill cellulose insulation, and dense-packed cellulose insulation.

The pros and cons mainly depend on which type you are going to choose. So, let us analyze the advantages and disadvantages of cellulose insulation:



Heat Resistance

Molding problem due to moisture absorption

Fire Resistance


Resistant to Mold

Messy Installation process


Health Concerns

Energy Efficiency


Advantages of Cellulose Insulation

Advantages of Cellulose Insulation

Heat resistance

The R-value of cellulose is about 3.2 to 3.5 per inch of thickness. The R-value refers to the measure of how well an insulation can resist the steady conduction of heat. This is because cellulose is made of paper and paper consists of wood fiber.

The very cellular structure of wood is such that it prevents leakage of air and thus is quite good at keeping heat out or keeping it locked. This essentially means that cellulose insulation will keep your home warm during winter and sufficiently cool during summer. Such a situation will also in turn reduce your electricity bills as the need for an AC or a heater will rarely be felt.

Fire resistance

In addition to being heat resistant, cellulose insulated walls are also fire resistant. In the event of a home fire, the cellulose insulation will essentially stop the fire from spreading rapidly and prevent wreaking havoc on life and property.

Resistant to mold 

A wall that is covered with mold is not only a sore for the eyes but also unhealthy for the people who live amongst such walls. Many report respiratory issues after years of living within molded walls.

Well, the good news is that cellulose insulation in walls offers complete mold resistance due to its ammonium sulfate and boric acid content.

Mold-free walls also mean that the quality of air inside the house will drastically improve and enhance the living condition greatly.


Since cellulose is made up of recycled paper, which in itself is very cheap; this makes the whole cost go down by a lot.

Compared to other insulation materials such as fiberglass, for instance, cellulose is way more affordable. The process in which the discarded paper is turned into cellulose is called hammer-milling and is also a very non-complicated and basic process.

Take the example of loose-fill cellulose insulation- it can be blown directly into the attic or wall cavity with a rented blower. The installation process is quite simple and can even be done by anyone with proper guidance and few rented equipment such as masks and blowers.

Energy efficiency

Besides being eco-friendly and biodegradable, installing a cellulose installation also reduces energy consumption.

Compared to a standard fiberglass installation, cellulose has a higher R-value. In attic insulation, using loose-fill cellulose insulation or dense-pack cellulose insulation prevents air convection inside the insulation which can lower the R-value at very cold temperatures.

In an experiment conducted to test and compare the energy consumption of cellulose and fiberglass, two identical buildings were built on two respective insulated platforms. The building with cellulose increased airtightness by 74% thus consuming 26% less energy than the building with fiberglass insulation.

However, since this test was done in a very short time, the results are also short-term. A conclusive result for the long-term performance of the two materials wasn’t obtained.

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Disadvantages of Cellulose Insulation

Disadvantages of Cellulose Insulation

Molding problem due to moisture absorption

You might be wondering how the issue of molding can be both a pro and a con. Well, the thing is cellulose is extremely moisture absorbent.

Other insulation materials usually expose the moisture in the walls instead of absorbing them but not cellulose. It is like a sponge that soaks in any leaking moisture from the wall and this can give rise to molds on the wall surface.

So, if you have a leaked plumbing system with cellulose insulation, you might be in for some trouble.


In comparison to other insulation materials, cellulose is much heavier. Since it weighs more, it tends to settle downwards towards gravity. This, however is a long-term effect and doesn’t happen overnight.

Due to this very reason, builders these days go for the wet variety of cellulose rather than the dry-blown one as it tends to sag quicker and faster than the wet one.

A sagging cellulose layer is detrimental to the insulation within the walls and may end up increasing your energy bill.

Messy installation process

Installing any type of cellulose insulation generates a lot of dust and debris and generally leaves a lot of mess.

The material cannot be neatly packaged. In the case of loose-fill installation, there are small pieces of fiber that have to be installed. These fibers, if ingested can be injurious to health, and thus the installer has to wear a special mask at all times while dealing with cellulose. 

Health Concerns

According to many health experts, continuous exposure to cellulose can be a cause of health issues. For one, the minute fibers of the material, if ingested can cause gastrointestinal problems.

Some are even of the opinion that the chemical components of cellulose can be a major cause for concern as they are fundamentally toxic and possibly carcinogenic.

The said chemicals are boric acid, ammonium sulfate, and sodium borate. The boric compounds are said to cause infertility in rats, although no similar effect has been reported in humans.

Health experts also opine that a cut or scratch if exposed to a cellulose layered wall can cause toxic poisoning.

Is Cellulose Insulation worth it?

Whether installing a cellulose installation is worth it or not is a subjective topic of debate. Where you live, the type of property, your financial condition, and the overall climate around the property – all of these are determining factors to answer that question.

In areas that experience extremes of weather, such as torrid sun and cold, getting cellulose insulation is a smart and cost-effective choice to enjoy a comfortable indoor temperature throughout the year.

However, in temperate places prone to a monsoon climate, cellulose insulation may lead to fast sagging of the installation.

Also, there is the factor of health issues that this material is said to cause and whether or not you choose to believe it.

All of this considered, cellulose insulation is indeed worth it. Its advantages are way too good to be true in that budget and you should go for it.

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Wrapping up

The possible health concerns that cellulose supposedly causes are probably its most noticeable disadvantage.

Whether you are looking to get cellulose insulation for your family home or any business-related property, the prospect of falling sick due to cellulose poisoning is scary. That said, the claims about the toxicity of the material are not based on concrete grounds.

The same boric compounds found in cellulose are also a component of soaps and eyewashes. It is essentially pulverized wood pulp and its advantages far outweigh its disadvantages.

If you are considering cellulose insulation in the walls of your property and need more insight on the whole process, then you should consult with a professional or an architect. They will be able to give you a breakdown of all the types of cellulose.

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