Are you a new homeowner, or do you want to change your insulation to improve its effectiveness? In this case, choosing the best insulation is your priority, and it is quite normal to be confused about the best insulating material for your home.

Both fiberglass and cotton insulation can be difficult to tell apart initially. It is so because both come as batts and are super easy to install. While most professionals say fiberglass batts narrowly outdoes cotton insulation, the former comes with certain downsides that are a cause of concern for house owners.  

This begs the question of which you should choose between the two insulations. Which poses fewer health issues? Which lasts longer? Which works best under pressure?

We’ve highlighted the cons and pros of both insulations to help you make your choice. Read on to discover them and find answers to your questions.

Fiberglass Insulation: What You Should Know

As the name connotes, fiberglass insulation is a material that consists majorly of glass particles. It works as an insulator by trapping air and stalling heat transfer. Usually, fiberglass appears in a blanket form and is cut into batts, yet can also be available as loose fill. You’ll find fiberglass batts in various thicknesses, which specify the resistance to heat flow.

The heat resistance for insulations is measured in R-value. Hence the R-value for fiberglass insulation is 5-7 per inch and ranges from R11 to R19 for walls up to R30 for attics and ceilings. 

Advantages of Fiberglass Insulation

One of the things people love about fiberglass insulation is the fact that it is easy to install in no time. Also, it is quite affordable, making it one of the most popular insulation for regulating temperature in the home. Read on for more benefits of this insulation!

  • Flexible: It is possible to get fiberglass in rolls and loose-fill and pre-cut panels, which make it super flexible for installation. Hence, it is possible to place this insulation between joists, studs, rafters, and any surface in need of insulation. Its flexible trait makes it a pocket-friendly option compared to other types of insulation.
  • Energy Efficient: Typically, fiberglass insulation is capable of lessening heating and cooling bills by 40% to 50%. Also, it saves energy and has a suitable R-value.
  • Fire Retardant: Fiberglass is made from recycled sand. The components make fiberglass naturally fire-resistant and decrease the chances of fire hazards. Sometimes fiberglass is treated with a fire retardant to enhance fire safety.
  • Cancels Noise: Fiberglass consists of a natural sound-dampening property that helps to lessen the noise coming into the house. Fiberglass is also referred to as acoustic insulation because of this feature and can be used in ducts, walls, and ceilings to lessen sound transfer.
  • Environmentally friendly: Fiberglass is made from about 30% recycled materials and is considered eco-friendly insulation.

Disadvantages of Fiberglass Insulation

Regardless of its many advantages, fiberglass insulation has some downsides that homeowners must be conscious of. The most significant cause happens during the installation process. Although fiberglass insulation is easy to install, a poor installation by non-professionals can lead to many issues as time passes. Below are some of these disadvantages you should know!

  • Coverage: Most fiberglass panels come pre-cut, so it is natural to face some difficult challenges during installation. For instance, crannies, odd shapes, and other irregularities can pose a challenge to the regular sizes of fiberglass batts.
  • Air Exchange: Fiberglass is less dense and helpful against air leaks compared to other insulations. Therefore, it is important to consider including an extra airtight seal when working with fiberglass. Other insulations are preferable and more efficient to prevent air change.
  • Moisture: Fiberglass doesn’t bode well in regions with high degrees of moisture. For instance, roof leaks and excess moisture in the attics and basement can spoil fiberglass insulation, causing mold and mildew in the long run. To prevent this or slow down the spoilage process, you can add a vapor barrier to prevent moisture from coming in contact with the fiberglass insulation.
  • Mold: The inability of fiberglass to hold moisture causes things like mold to settle in. The moment mold infests fiberglass insulation. There is a need for immediate change to prevent continued damage to the house’s walls and structures.

Cotton insulation: What You Should Know

Cotton Insulation is obtained from small cellulose fibers in denim jeans and other varieties of clothing. Its production gradually began in the 90s from the tremendous percentage of scrap denim gotten from clothing manufacturers. These fibers are bound together in batts which become lenient to install in ceilings, walls, floors, and attics. 

These insulation products are measured to fit between the studs of homes and come in a variety of widths for different R-values. Cotton insulations have an R-Value that ranges from 3-4 per inch.

Advantages of Cotton Insulation

There are lots of benefits homeowners get from using cotton insulation. Here are some of them!

  • Improves Structural Integrity: Cotton insulation enhances the structural integrity of the home since it is usually dense. This increase in density lets it fill out the wall cavity properly to keep out oxygen, which lessens the risk of fire spreading into wood walls. 
  • Environmentally Friendly: One of the major benefits of cotton insulation is that it lets you reuse and recycle materials that would otherwise end up in landfills. 
  • Soundproof: Cotton insulation serves as a terrific soundproof system for houses. In noisy areas with rain tracks, high winds, or noisy neighbors, this insulation type offers you protection from them indoors.

Disadvantages of Cotton Insulation

  • Prone to Water Damage: Cotton insulation is prone to water damage. Hence, you need to endure that picking leaks is fixed immediately. If not, it can destroy your insulation and the need for costly renovations in your home.
  • Zero Fire Resistance: Cotton insulation is not fire-resistant at all. Therefore, you need to support it with borate flame retardant products that can help reduce your home’s susceptibility. Some natural flame retardant products include Boric acid, borax pentahydrate, and borax decahydrate. They provide protection for your cellulose insulation and additional protection from insect infiltration.
  • Mold: Even minimal moisture leaks can cause the fibers in cotton to become compressed. In return, this can lead to the development of mold. One way to reduce this is to install water leak detectors that can alert you of even the little water leak to avoid damaging your cotton insulation.

When Should You Choose Cotton Insulation Over Fiberglass?

Recent studies have discovered that Fiberglass insulation in home studs provides a particular risk to inhabitants. During the installation process, the material causes skin and eye irritation. Also, inhaling small fiberglass particles can cause respiratory issues and lung damage.

In this light, choosing the more natural Cotton insulation lessens your exposure to these hazardous health issues.


Justin's been in construction for over 20 years in both new build and renovation. With experience in both commercial and residential construction, he specializes in healthier and more energy-efficient homes.

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