9 Pros and Cons of Cellulose Insulation


Cellulose insulation is a favorite of the green home building movement. Insulation is a recycled insulation which makes it a very popular material to insulate buildings. It is made from newspaper which is always in ample supply. There are several different ways that the newspaper is processed. In one process the newspaper is cut with large blades on a machine into small enough pieces to fit through a screen.

The newer process is called defiberization which uses high intensity air that blows the newspaper apart back into individual fibers. This process is the favored process because you get a much denser material. Once the newspaper has been reduced to fibers a mold inhibiting chemical and a fire retardant chemical is mixed with the fibers. In some cases dry binders are mixed in.

The newly formed insulation is bagged up and shipped to building suppliers. There are some really great pros when it comes to this type of insulation and some potentially pretty worrisome cons. Understanding the pros and the cons can help to better understand if this insulation is something you want in your home.

List of Pros of Cellulose Insulation

1. Helps Cut Down On Waste.
The United States generates about thirteen million tons of newspaper each year. That roughly equates to about 100 pounds of newspaper for each person. Before the idea of recycling really took hold, newspapers wound up in the landfill.

There are a lot of things that old newspaper can be recycled into but some of the processes can really put a drain on the environment and can actually be more costly than simply making up new paper. For example to turn newspaper back into usable paper it requires that ink is removed and that the paper is bleached. This requires quite a bit of energy and the use of harsh chemicals that can generate pollution.

Turning newspaper into insulation does not require the de inking process nor does it require a bleaching process as a matter of fact it does not even require that much energy which makes it a much better option.

2. Low Tech Process.
Changing newspaper into insulation is a very low tech process which can be done anywhere. This means that manufacturing shops can be small and can be spread out which means that trucking materials long distances would not be necessary.

When you compare cellulose insulation manufacturing requirements to fiberglass requirements it is easy to see why green builders choose cellulose. Fiberglass manufacturing is an intricate process that requires a large space to manufacture which equates in many cases long distance deliveries. Long distance deliveries equal more fuel needed to deliver. Cellulose manufacturing takes up a fraction of the space, a fraction of the energy and can be manufactured easily and multiple points to keep long distance delivery down to a minimum.

3. Energy Conservation Performance.
Cellulose performs better than fiberglass insulation when it comes to reducing the cost of energy. When compared under the same conditions fiberglass insulation increases air tightness by 41% over an uninsulated building while cellulose insulation increases air tightness by 74%.

Unlike fiberglass insulation which improves with the increase of density, cellulose insulation offers the same protective values across the board regardless of material density.

4. Easy Installation.
Cellulose installation can be done in either a dry installation method or a wet method. It can be blown in by using air or spread by hand. The mix can be wet or dry when applied. There are no measurements, no cutting, no rolling out the insulation. It is an easy to do install.

Retrofitting homes with this type of insulation is also relatively easy. Pieces of siding are removed and small holes are drilled in the wall and the cellulose is blown in.

List of Cons of Cellulose Insulation

1. Strapped Resources.
Boron is a key chemical that is used in the processing of cellulose insulation (used to make Boric acid) and the Boron reserves are low. There are only three known mines in the world that contain Boron ore. Two in California and one in Turkey. At the current rate of demand it is estimated that the three of these mines can only supply enough Boron for the next 50 years.

Of course the fact that we are running out of Boron is an issue but the larger issue is that the act of mining generally speaking is one of the worst things we can do to the environment. It takes a huge amount of fuel to mine and it can cause great upset to the earth that is being mined.

So while recycling newspapers into insulation is a great idea it is not without fault and certainly not without a dire effect on the environment.

2. Health Concerns.
How safe is cellulose insulation? There are a few chemicals that are used in the process that are fire retardants that are also known carcinogens. Some of the chemicals are so dangerous that if an infant swallowed 1/8th of an ounce of some of the chemicals it would be fatal.

Apparently according to the British Journal of Industrial Medicine in an article published in 1992 “Boric acid itself is a toxic material and can be lethal to humans when ingested in gram quantities. It is not considered that the inhalation of cellulose insulation dust could approach this lethal toxicity but the heavily impregnated respirable cellulose dust will liberate the readily soluble boric acid in significant amounts in lung tissue. Symptoms of sublethal toxicity to boric acid include abdominal pain, liver, kidney, and lung dysfunction and severe exfoliative dermatitis.”

Ammonium sulfate is also often used and it can decompose over time from moisture and heat, it can release sulfuric acid that is corrosive to any material in comes in contact with especially metal beams and girders.

3. It’s a Mess.
Unlike other insulation, cellulose is not neatly packaged. It is just pieces of fiber. It is hard to clean up should you decide to revamp your attic. In other words once you have cellulose insulation you are pretty much stuck with it.

4. Usefulness.
Cellulose has a useful life limit after a point it loses it fire retardant ability which can make it a hazard in your home. Unfortunately the life span is a bit hard to pinpoint. Of course as mentioned above once it has outlived its usefulness getting cleaning it out can be a difficult task.

5. Fire Hazard.
Once it loses its fire retardation it can easily become a combustion hazard since its original material (newspaper) is highly combustible. This can be an unstable material for insulation.


Cellulose insulation is quickly becoming a very popular choice for builders. As the processing improves and other testing is done to figure out how to utilize other chemicals that are more readily available the safety rating will improve and this may easily elbow out other forms of insulation.

It is certainly worth considering. Speak to a building contractor about cellulose insulation to get more information that can help you to decide if this is a material you want to use.