Cellulose Insulation Pros and Cons

Cellulose insulation has become an increasingly popular material along with fiberglass and mineral wool, and it’s easy to see why. Cellulose insulation is made from recycled newspaper, so it’s environmentally friendly, durable, and less expensive than traditional fiberglass insulation.

If you’re considering this insulation for your home or business, here are some pros and cons to help you make the right decision.

The best eco-friendly optionMessy installation process
High R-value for heat resistanceEasily absorbs moisture
Armed with fire retardantsSags and settles over time
Exceptional mold and mildew resistanceFire retardants used pose health risks
More energy-efficient than fiberglassLimited useful life
Affordable and cost-effective
Pros and cons of cellulose insulation

Before going into details, let’s know the basic details about cellulose insulation.

What is cellulose insulation?

Cellulose insulation is made from recycled paper products and is one of the most eco-friendly insulation options on the market. Its composition is up to 85% recycled newspaper fiber, and the remaining is fire retardant substances such as ammonium sulphate and boric acid. In comparison, fiberglass is only 50% recycled material.

Picture of cellulose insulation
Picture of cellulose insulation

How is cellulose insulation manufactured?

There are many ways of manufacturing cellulose insulation. The most common process is called ‘defiberization’. The newspaper is cut into small pieces using a machine with blades. Then, high-intensity air blows these small pieces into fine fibers. Lastly, the fiber is treated with fire retardants and other chemicals to make it resistant to pests, mold, and mildew. 

What are the different types of cellulose insulation?

Most insulations come in more than one form, such as batts, sprays, or loose-filled. Cellulose insulation comes in three different types, so it’s essential to know the difference before deciding which type to use in your home.

1. Loose-fill cellulose

If you’re looking for insulation that can be easily added to your existing home, loose-fill (blown-in) cellulose is a great option. You’ll need a blowing machine to blow the insulation into the attic cavities and floor. Reasonable access to the attic will help blow the insulation into every nook and corner easily. This insulation has an R-value of 3.5 for one-inch thickness.

2. Dense-packed cellulose

It is an excellent option for insulating walls and floors of existing or newly constructed buildings. This insulation flows like a liquid into cavities or cracks, where it solidifies to provide air-tight insulation. For this reason, it works perfectly to insulate or seal any cracks in areas that are difficult to reach. It also has the same R-vale of 3.5 as loose-fill cellulose to provide adequate insulation.

3. Wet-spray cellulose

One of the most popular types of cellulose insulation is wet-spray cellulose. This type of insulation is applied with a sprayer that uses water to wet the cellulose fibers and bind them together. Wet-spray cellulose provides an excellent seal against air and moisture and can be used in new construction and retrofit projects.

Pros of cellulose insulation

Cellulose boasts many advantages that make it stand out from other insulation types, including fiberglass and rock wool. These advantages make it more effective to keep your home warm and cool in the summer. Let’s discuss some of the many benefits you can expect from cellulose insulation.

1. Eco-friendly option

One of the best things about cellulose insulation is that it is eco-friendly. It is made from recycled newspapers and other recycled materials, so it helps reduce waste. Plus, it is a natural product that does not off-gas or release harmful chemicals into the environment. 

When newspapers are recycled to make other products, a bleaching process involving harsh chemicals is used to remove the ink. However, recycling newspaper into cellulose doesn’t require eliminating ink, so there aren’t any chemicals involved in the process, making it environmentally friendly insulation.

2. Good R-vale for heat resistance

Cellulose insulation has a great R-Value of 3.5, meaning it does a great job keeping the heat inside during winter while keeping the heat out during the summer. The wood fibers that make cellulose insulation are naturally heat resistant, so they don’t let air pass through easily, making them an excellent insulation choice. It can lead to lower energy bills, as your home will be better insulated against the elements.

3. It is fire retardant

One of the significant advantages of cellulose insulation is that it is fire retardant. It means that it can help prevent the spread of fire in your home or office by having an additional layer of protection if there is a fire. It has up to 20% fire-resistant chemicals such as boric acid and other fire retardants borate compounds that were first introduced in the 1950s, which made cellulose a popular insulation material in construction.

4. Resistant to mold and mildew

Mold and mildew can destroy your home, causing health problems and costly damage. But luckily, cellulose insulation is naturally resistant to both mold and mildew. It makes it ideal for homes in humid climates or areas with high moisture levels. Also, the introduction of boric acid and ammonium sulphate has made this insulation hypoallergenic. Mold-free walls mean that the air quality inside the house doesn’t pose any health risks for vulnerable family members.

5. Energy-efficient

Cellulose offers the same R-values for all types of cellulose insulation. It has consistent heat resistance regardless of the density making it more energy-efficient than other popular insulations such as fiberglass. Also, studies show that cellulose increases airtightness by more than 70% compared to fiberglass, which increases airtightness by around 40%.

6. Cost-effective

It is one of the most cost-effective ways to insulate your home. It uses newspapers available in abundance, so they come in cheap for recycling. Also, the recycling process doesn’t require any chemicals for bleaching, which again cuts down on cost. So, cellulose insulation is a very affordable option for insulation. It is also a more straightforward installation process; you can rent the blowing machine, which will not cost you much.

Cons of cellulose insulation

While there are many advantages to cellulose insulation, there are also some disadvantages you should be aware of before deciding to use it in your home. Here are five of the most important ones to consider.

1. Installation can get messy and dusty results

One of the most significant disadvantages of cellulose insulation is the amount of dust it creates. The insulation is made from recycled newspapers and other materials, which makes it very abrasive. It can lead to a messy installation process and be challenging to clean up afterward. You can also expect the recirculation of cellulose duct throughout your home if you have an HVAC system.

2. Easily absorbs moisture

Cellulose is treated with mold-resistant chemicals, but there are still concerns for mold and mildew because the materials can easily absorb moisture. Many other insulation materials don’t absorb water, so the water is immediately visible on the walls if there is a leak. On the other hand, cellulose absorbs moisture and provides breeding grounds for mold and mildew. 

3. Tends to sag and settle

A common complaint about cellulose insulation is that it tends to sag and settle over time. It can create gaps and voids in your insulation, leading to heat loss and drafts. Cellulose insulation weighs more than other types of insulation, so gravity has more to do with settling than anything else. Settled cellulose also loses its R-value, which decreases its insulation efficiency. However, wet-spray cellulose doesn’t sink as much as loose-filled cellulose.

4. May contain carcinogens

The chemicals used in treating cellulose to be fire resistant are known carcinogens. It can cause cancer if people are constantly in contact with or exposed to them. These chemicals are also fatal if infants accidentally swallow even a tiny quantity. Ammonium sulphate used for mold resistance can lose its quality due to heat and moisture and can cause metal beams and other metal installations to corrode if it comes in contact with them.

5. Limited useful life

Cellulose has a limited useful life, which can lose its fire and mold resistance qualities. It makes cellulose vulnerable to fires, and newspaper, the primary material used in this insulation, is highly combustible. Cleaning cellulose out for replacement can also be a difficult task.

Frequently Asked Questions

How long does cellulose insulation last?

In ideal conditions, cellulose insulation can last up to 30 years. However, it usually doesn’t happen as many factors contribute to rendering cellulose useless well before 30 years. It is not exceptional to cellulose as every insulation can degenerate for different reasons. Just weigh the pros and cons of each insulation and, most importantly, your budget when deciding on the suitable insulation according to your home needs.

Is cellulose better than fiberglass?

When you compare identical sizes of both insulations, cellulose provides better thermal performance than fiberglass. Cellulose has an R-value of 3.2 to 3.5 per square inch, while fiberglass has an R-value of 2.2 to 2.7 per square inch, making cellulose better at controlling heat transfer. But it doesn’t mean that cellulose will perform well in every situation while fiberglass will not perform as well. Depending on your home’s specific needs, you can choose any of these insulations for efficient performance.

fore more info, refer: Cellulose vs fiberglass insulation

What is the best blown-in insulation?

Cellulose is a good option if you’re looking for insulation that will seal the heat well. Many types of loose-filled or blown-in insulation besides cellulose work exceptionally well. Some examples are fiberglass, cotton, and mineral wool. However, fiberglass has been the most popular choice among homeowners because its advantages outweigh its disadvantage making it an excellent insulation for tight spots and around pipes.


After weighing the pros and cons, you may decide that cellulose insulation is the right choice for your home. It is an environmentally-friendly option, but it can also save you money on your energy bills. However, do your research to ensure that cellulose insulation is suitable for your climate and home.

Charles John

Experienced HVAC technician with 8 years of experience in the industry. Capable of handling all sorts of heating and cooling equipment as well as proficient in operational management, construction-related techniques such as preventative maintenance, electrical troubleshooting and AutoCAD

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