What Are The Types Of Loose-Fill Insulation?

Home insulation proves to be vital when it comes to providing resistance to heat flow, lowering your heating and cooling costs, and especially improving the level of comfort in your home. Loose-fill insulation fits these criteria when choosing what home insulation to install. Now, you may be wondering what the types of loose-fill insulation are? Here’s what we've discovered about loose-fill insulation types that you need to know. 

There are three most common types of loose-fiber insulation, namely:

  •  Cellulose
  •  Fiberglass 
  •  Mineral (Rock or Slag) Wool. 

Keep on reading to know more about loose-fill insulation and what type is best for your home. Also, get to know what factors you should consider in choosing the right loose-fill insulation to use.

Worker with a hose is strewing ecowool insulation in the attic of a house, What Are The Types Of Loose-Fill Insulation?

What is loose-fill insulation and its application?

Compacted particles of foam, fiber, and other materials are what loose-fill insulation is made of. An insulation material is formed by these small particles filling any space without disturbing any structures or finishes. Since the finished installation is seamless, loose-fill insulation can provide better insulation by up to 22%.

Loose-fill insulation is used in roof and attic insulation and soundproofing. Its ability to fit makes it well suited for retrofits and difficult location installations. Loose-fill insulation can be applied by directly pouring it from the bag or with a blower.

What are types of loose-fill insulation and their properties?

As mentioned above, loose-fill insulation most commonly has three types, namely cellulose loose-fill, fiberglass loose-fill, and mineral (rock or slag) wool loose-fill. Recycled waste materials are the primary source of material for these types of insulation. Find out more about these types below.


Eco-friendly cellulose insulation made from recycled paper

Cellulose loose-fill insulation is primarily produced from recycled papers, generally 82-85%, and sometimes with a mix of wood fiber. These materials are treated with fire retardants, such as fire borates and sometimes blended with ammonium sulfate to eliminate their combustible properties.

Cellulose insulation materials are sometimes mixed with some natural fibers like sheep's wool, cotton, hemp, and straw. The R-value or insulation value of cellulose loose-fill insulation is 3.7 per inch, which is considered the highest among other types. Characteristics of cellulose insulation are fluffy, gray to brown color, and papery texture.


New wall with fiberglass insulation

Fiberglass insulation is created by melting glass and spinning it into small fibers. 40% to 60% of recycled glass is mostly contained in fiberglass insulation, according to the U.S. Department of Energy. It also comes in two forms: pink batts and a loose variety usually blown into walls and attics.

Depending on the color of the resin used to homogenize glass fibers, blown fiberglass insulation usually comes in pink, yellow, green, or white color. The R-value of most fiberglass insulation is 3.14 per inch, according to Inspectapedia.

However, if you opt to use fiberglass insulation, you have to note that this material can expose you to the risk of some respiratory hazards. Your lungs can be damaged by some airborne fiberglass particles. Another concern to worry about is the growth of hazardous molds when fiberglass insulation is left moist.

Click here for this ceramic fiberglass insulation from Amazon.

Mineral (rock or slag) wool

Worker in protective goggles and respirator insulating rock wool insulation in wooden frame for future house walls for cold barrier

According to the U.S. Department of Energy, the term mineral wool typically refers to two types of insulation materials:

  1. Rock wool- synthetic material consisting of natural minerals like basalt or diabase
  2. Slag wool- synthetic material from the waste matter formed on the surface of molten metal known as blast furnace slag

Mineral wool insulation is made up of 75% recycled materials from manufacturing operations. Although most mineral wool looks like cotton, it is really comprised of mineral fiber. It can also be white, gray, or brownish in color.

Mineral wool insulation has a lot in common with fiberglass insulation. The sole difference is that fibers are formed from molten rock that is spun into a fibrous material rather than molten glass. It has an R-value of 2.5 to 3.75 per inch.

Mineral insulation has the disadvantage of being relatively heavy and requiring substantial support. When compared to fiberglass, however, its weight makes it less prone to get airborne.

Click here for this mineral insulation from Amazon.

What are the factors to consider in choosing what type of loose-fill insulation you should use?

In choosing what loose-fill insulation is suited to our needs, a few factors must be considered. Here are some factors that we researched:

R-value (Thermal Performance)

The R-value of a material is a measurement of its resistance to heat transmission through it, and it's a significant indicator of high-quality insulation. The higher the R-value, the better it is insulating your home thus lowering the cost of your energy bill.

As mentioned above, these are the R-values of different types of loose-fill insulation:

  • Cellulose- 3.7 per inch
  • Fiberglass- 3.14 per inch
  • Mineral (rock or slag) wool- ranges from 2.5 to 3.75 per inch


You may think that soundproofing must be the least of your concern in choosing a good insulation material. However, adding quality insulation has the benefit of making your home more soundproof. Due to the density of the insulation, it diminishes unwanted noise from the outside making you take control of your environment.


Another important factor is the flammability of the insulation material. As a homeowner, the last thing you should be worried about is your house being in danger of catching fire. Most, if not all, loose-fill insulation materials are treated to fire retardants to eliminate the flammability of the materials.

Health Risk

Choosing a good loose-fill insulation material also means choosing a safer material. Some materials may pose serious health risks and can become allergens. In addition, some materials can irritate and damage the lungs. The formation of mold not only impacts health but can also damage the quality of the material.


Considering the cost-effectiveness of the material is also one factor to consider when you decide to use loose-fill insulation. Most loose-fill insulation is relatively inexpensive since most of the materials used are recycled. Moreover, the effect of good insulation will significantly result in lower energy bills.


Sustainability is also an essential factor in choosing good insulation. This movement will help lessen the carbon footprint and will leave a remarkable impact on the environment.

What type loose-fill insulation is best to use?

Loose-fill fiber and sheep wool insulation in walls

While there is a variety to choose from, you may wonder what type is best to use? Based on what we researched and considering the above-mentioned factors, here's what you need to know.

In terms of R-values, cellulose insulation has the highest with 3.7 per inch compared to the 3.14 per inch of fiberglass and 2.5-3.75 of mineral (rock or slag) wool. However, the best type to use for soundproofing is loose-fill cellulose and fiberglass. You can read more about soundproofing in an article previously posted here.

Fiberglass has high resistance to fire due to its nature. Mineral wool is extremely resistant to fire and can withstand temperatures of over 1,000 degrees Celsius (1,832 degrees Fahrenheit). While cellulose insulation isn't fireproof, high amounts of fire retardants are added to help it resist combustion.

While it is not new that fiberglass and mineral wool insulation can cause irritation and lung damage, cellulose insulation also poses health risks due to its property to absorb moisture. Excess moisture can become a breeding ground for mold and other pests which can affect your home.

It is indeed true that these types of loose-fill insulation are cost-effective. However, fiberglass insulation is slightly cheaper compared to cellulose insulation. On the other hand, mineral wool insulation costs 25 to 50 percent more than fiberglass insulation.

Since all of these types of loose-fill insulation are made of recycled materials, there is no question with regards to the sustainability of these materials. Fiberglass and mineral (rock or slag) wool insulation contain 40-60% recycled content depending on the manufacturer.

Furthermore, according to the International Association of Certified Home Inspectors, loose-fill insulation usually lasts more than 100 years.

While it is debatable whether cellulose is better than fiberglass, choosing what type of loose-fill insulation to use is up to you. However, it is important to note that the best type to use is the one that is convenient and is best suited for the installation you need.

In Closing

In a nutshell, insulation significantly helps in regulating the heat flow within the home. Whether it's cellulose, fiberglass, or material wool insulation, there are key factors to consider in choosing what type of loose-fill insulation to use. These key factors include, but are not limited to, R-value, soundproofing, health risk, cost, and sustainability. We hope you found the answers to your question!

Before you go, do you have additional questions regarding loose-fill insulation or insulations in general? To learn more, you can read these articles:

Can You Mix Different Types Of Insulation?[Esp. Blown-In]

Can You Mix Fiberglass And Cellulose Insulation?

Best Insulation For Ceiling Under Roof

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