What is the R-Value of Cellulose Insulation? [With Chart]

So, you have been contemplating your decision to install cellulose insulation, and you have read dozens of articles concerning the same. But to no avail, we bring you this article that mentions every detail that you must know about cellulose insulation, especially its R-value.

The R-value of a material is the measure of the thermal resistance it can offer. It is usually the amount of resistance it offers to the flow of heat or cold through it. The higher the R-value, the more efficient it is at insulating.

Cellulose has been used for a very long time by households and commercially. It is composed of recycled newsprint and denim. Which makes it the most eco-friendly option available in the market for insulating your house.

Now let’s get back to your question about what is the R-value of cellulose? Read along to know better about the R-value of the material and the various types of cellulose insulation that are available in the market, all with different R-values for different applications.

What is the R-Value of Cellulose Insulation?

R-Value of Cellulose Insulation

Cellulose insulation provides efficient insulation to your walls and will not be harmful to the environment. So if you are an environment vocalist, then this will fully suit all your needs.

Cellulose is also a great air blocker. It blocks all the air, which results in better insulation for the house. It helps to reduce heat loss through convection, making it an excellent insulator.

The R-value of cellulose insulation is between 3.2 to 3.8 per inch of thickness, more than enough to insulate your attics and walls. It is eco-friendly, easy to install, has a high R-value, and has excellent flame retardant properties.

Here is a quick reference table for the cellulose R-values of the different types of cellulose insulation:

Type of Cellulose Insulation


Loose-fill cellulose

Around 3.5 per inch of thickness

Dense-packed cellulose

Between 3.8 and 4.0

Wet-spray cellulose

3.6 to 3.8 per inch

Here is a brief description of the types of cellulose insulation and their corresponding R-values. There are three types of cellulose insulation:

Loose-fill cellulose insulation

Also known as the blown-in cellulose insulation, is widely used in the attics, and the installation is done with the help of a blowing machine. It is in the form of granules and fibrous. It is made of cardboard, paper, and paper stock.

It is hassle-free in the application as it just has to be blown in the cavities and attics that require insulation. The R-value of loose-fill cellulose is around 3.5.

Dense-Pack Cellulose insulation

Dense-packed cellulose insulation is widely used to insulate ceilings and for wall insulation. It does not require a vapor barrier or ventilation. It is done by packing as much material as possible in the given space for insulating it.

Due to its dense packaging, the R-value of this type of cellulose is the highest, and it is the best insulation available if you want to install cellulose insulation in your house. The dense-pack cellulose R-value is between 3.8 and 4.0.

Wet-Spray Cellulose insulation

In this type of cellulose insulation, water along with a binder compound is added to the insulating material, which gives a liquid form. Then this liquid form is sprayed into the insulating space.

The binder compound is added so that the cellulose remains intact in the insulated space and does not start losing its grip from there. This property of the wet-spray insulation helps to seal the space, and insulate the space simultaneously. The R-value of wet-spray cellulose insulation is 3.6 to 3.8 per inch.

Don’t miss:

Pros and Cons of Cellulose Insulation
R-Value of Fiberglass Insulation
R-Value of Spray Foam Insulation
Pros & Cons of Spray Foam Insulation

Does cellulose insulation lose R-value over time?

Does cellulose insulation lose R-value

The simple answer is yes! It does lose its R-value over time. It tends to lose its thickness due to environmental factors. Losing thickness causes it to lose its R-value. It begins to settle with time.

It causes aeration within the material, causing the R-value to decrease by 15-20%. And if it catches moisture or is installed improperly, then there may be a further reduction in the R-value of the material.

So, in conclusion, it does lose its R-value over time, if exposed to certain external conditions, the decrease in the R-value of the insulation will speed up significantly.

R-values of other insulating materials compared to cellulose

R-values of other insulating materials compared to cellulose

Even though we all are very well aware that spray foam insulation has the highest R-value, it is costly. It cannot be afforded by everyone.

But compared to fiberglass insulation, cellulose insulation has the highest R-value per inch, and it is eco-friendly too.

So, if you are on a tight budget, then the best option for you will be cellulose insulation. Cellulose insulation is very effective for insulating your spaces, as it has got a sufficient R-value and it is cost-efficient too.

Don’t miss:

Crawl Space Insulation
R-Value of Rockwool Insulation
What Insulation Has the Highest R-Value Per Inch
When do you need a vapor barrier

The Bottom Line

Cellulose insulation is the best choice for you if you are looking for an eco-friendly alternative to insulate your house. It is cost-efficient too, so it won’t empty your pocket also. Plus, there is a great variety available within it. You can choose which type suits you the best and install it.

While you can use loose-fill cellulose insulation in your attics and wall insulation, for your ceilings you can apply dense-packed cellulose insulation. The R-value of these materials ranges between 3.5- and 4.

The blown-in cellulose foam R-value is around 3.5. For the wet spray, it is around 3.6-3.8 and for the dense-packed, it is between 3.8- 4.0. The quality that you get at such an affordable price is incomparable. You also are helping the environment by installing cellulose insulation.

You can try to make it a fun DIY project, but if you are not very confident with the outcome, then we will advise you to ask a professional to install it. They know the proper techniques and will give your house a perfect finish with the correct insulation.