What is Cellulose Insulation?

Tricia Christensen
Tricia Christensen

Cellulose insulation is material used to insulate between interior and exterior walls and other structures of buildings. This form of insulation is made from a variety of things that were at least originally plant matter. Numerous people throughout history have used forms of cellulose insulation. It was even employed in the famous Monticello, the home of Thomas Jefferson.

Monticello, the home of Thomas Jefferson, had cellulose insulation.
Monticello, the home of Thomas Jefferson, had cellulose insulation.

The attitude toward cellulose insulation has undergone gradual change. Concern about safety of some of the products used in the 1970s led to greater regulation, and increased the sales of its main competitor at the time, fiberglass insulation. After fiberglass reigned supreme in the insulation market for several decades, studies on cellulose insulation began to prove some interesting facts about it.

Cellulose insulation can attract termites.
Cellulose insulation can attract termites.

For instance, researchers found that this form of insulation might help protect homes from significant fire damage because it is so compact there is little room for oxygen, which fire requires to keep burning. Another interesting aspect of this insulation is that with the exception of chemical treatments applied to it, it is considered a much “greener” building material.

It uses primarily recycled materials like paper and naturally produced fabrics. In fact, when the California Academy of Sciences rebuilt their facility in San Francisco in the late 2000s, they opted to use recycled denim as insulation. One factor in choosing this green method was the low embodied energy (amount of energy it takes to produce a product) in denim insulation, as compared to the embodied energy of fiberglass.

There are several types of cellulose insulation that can be used in buildings. These include loose fill, low dust, wet spray and stabilized. Loose fill can be blown into areas of space requiring insulation. Low dust is treated with certain additional products, which may be useful if people are allergic to dust from things like newspapers. Wet spray cellulose insulation has water added to it, and may be the most effective insulation form, and stabilized cellulose bears some similarity to it.

There can be some significant long term cost savings in using cellulose insulation. It tends to keep in heat better, or keep it out depending upon exterior temperature. The one thing that remains challenging is finding people skilled in applying it. It can take some work to find those with extensive experience in installing different forms of this insulation. Another potential disadvantage is that the ingredients in this insulation may attract termites. However, treatment with borate, which is usually standard, tends to discourage termites.

Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent wiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments


What kind of noise reduction properties does cellulose insulation have?

I know that there are special types of insulation that you can buy that are designed to control sound escaping from an area. I had a friend who put insulation in his basement so that his kids could have their own play area, and the adults would have some peace and quiet.

The article says there is very little air in the material, so I would assume it is a pretty good insulator of both sound and heat. Am I right, or would it just be better to install something like sound reducing drywall or a special wall covering?


@cardsfan27 - Interesting observation. I was thinking, too, that straw would have been common then and probably would have been a decent insulator.

How much is the cost difference between getting cellulose insulation in your home versus fiberglass or polyurethane insulation? I assume because it is less common, that the overall cost is higher. I do know that there are a couple of companies in my area that specialize in this type of insulation.


I was watching a home improvement show recently where they were using the denim insulation that was mentioned in the article. It was interesting to see the material applied. It was a blue tint, but it looked almost like wet, ground up pieces of paper that were being spraying into the wall.

What kind of cellulose material was use in Monticello? Obviously, he would not have had access to denim or tools that could blow in the insulation. My guess is that it would almost have to have been ground up plants or maybe even sawdust. I doubt most houses at that time had much insulation, so this was probably a very expensive addition.


I love the idea of being able to apply more environmentally sustainable insulation! I have recently been looking for options to replace the insulation in my attic since it is getting fairly old, and I think it is starting to lose effectiveness.

Are there any forms of cellulose insulation available at home improvement stores that I might be able to look at? Unfortunately, I live in a fairly rural area, and I doubt there is anyone around who would have the equipment and training to install this type of insulation. I will definitely call around and see if I can find someone, though.

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