Is Mineral Wool or Fiberglass Insulation Better? Comparison

Insulating your home requires choosing befitting materials for the job by comparing the numerous alternatives and selecting the best. Mineral wool and fiberglass insulation are two of the commonest options you are presented with in an insulation project. Which is better?

Mineral wool and fiberglass differ significantly in some areas regarding insulation. While mineral wool is more expensive, rigid, and durable, fiberglass is cheaper, fluffier, and has a lesser R-Value. Mineral wool melts less rapidly than fiberglass, making the former the more appropriate insulation type if the deployment environment has high temperatures.

In this article, you’ll get a more in-depth comparison of these two materials to help determine which is better.

Pros and Cons of Fiberglass Insulation

Fiberglass is the most commonly used insulation method today, and it’s available in blankets and loose-fill.

Its cost-effectiveness and ease of installation are among the reasons that make it a preferred choice among homeowners. However, it has other advantages as well.

Here are some of the advantages and disadvantages of fiberglass insulation.

Pros of Fiberglass Insulation

  • Fiberglass insulation is cheaper to buy and install than most other insulation materials. With the price per square foot not exceeding $1.30 in most places and the material being one of the best for your insulation work, it’s a real value for money.
  • Fiberglass poses little or no threat to the environment because the insulation material is made from recycled glass.
  • Fiberglass insulation is long-lasting, so you wouldn’t need to get your insulation redone every so often. Well-installed fiberglass insulation can last up to 50 years compared to other insulation types, which last around 10-30 years.

Cons of Fiberglass Insulation

  • Fiberglass can cause skin irritation if it comes in direct contact with the skin and can cause damage to internal organs if inhaled. For maximum safety, it’s best to employ a qualified insulation contractor to help with the process.
  • The R-Value of Fiberglass insulation decreases with time, causing the material to wear and sag after years of use.
  • You may need to install a separate vapor barrier because fiberglass doesn’t prevent water and or moisture from entering your home.

Pros and Cons of Mineral Wool Insulation

Mineral wool insulation is made from natural materials rather than recycled glass. It is one of the most common insulating materials used in the United States and Canada. 

There are two main types of mineral wool insulation: rock wool and slag wool.

Like fiberglass, mineral wool also has its advantages and disadvantages, which this section will explain in detail.

Pros of Mineral Wool Installation

  • Mineral wool insulation is hugely durable, thanks to the raw materials used in its production. As a result, this material’s insulation quality and R-value typically remain unchanged over time.
  • Mineral wool is soundproof, making it a preferred insulation material for residential buildings in noisy neighborhoods.
  • Mineral wool insulation is probably the easiest to install among other insulation materials, with less likelihood of damage during installation, all thanks to its rigidity.

Cons of Mineral Wool Insulation

  • Mineral wool insulation is usually more expensive than most other insulation types, making them less favorable to people on a budget, which partly explains why fiberglass is more popular.
  • Mineral wool insulation is harder to handle during installation because of its weight. You’ll need more people to install the material than fiberglass, making the installation process more expensive.
  • Finesse is necessary when handling and installing mineral wool as the stone fibers can cause skin irritation if they come in contact with the skin. Also, accidentally inhaling or ingesting the tiny silvers can cause various health issues. It’s advisable to wear protective equipment while handling the material.

That’s all there is to know about the pros and cons of the two most common insulation types. The following section will discuss the differences between fiberglass and mineral wool insulation.

Is Mineral Wool or Fiberglass Insulation Better?

Several metrics help industry experts determine what insulation method is better. When you apply these metrics to fiberglass and mineral wool, which of them will come out better?

Here you go:

1. R-Value

R-value is an agreed-upon measurement of the thermal resistance of a material. To determine the R-value, you can also use other vital elements like moisture accumulation, temperature, and aging.

Calculating the R-value multilayered installation is done by adding the R-Value of individual layers.

The higher the R-value of a particular material, the better. Mineral wool generally has a better R-value than Fiberglass insulation at around 3.0 and 3.3 per inch. In contrast, fiberglass has about 2.2 to 2.7 per inch of thickness.

2. Resistance to Moisture

Good insulation material should be both water and fire-resistant. Mineral wool insulation seems to be better in both aspects as it’s also more resistant to moisture.

Water accumulation tends to increase the risk of rotting, corrosion, and growth of dangerous microorganisms in the material.

Mineral wool is more resistant to moisture because it has hydrophobic properties, aiding it when in contact with water and other fluids.

Fiberglass, on the other hand, holds the absorbed water, and if you don’t get rid of the fluid, it can damage it and reduce R-value.

3. Durability

Both materials can last for years after installation. Mineral wool insulation is more durable than fiberglass and less likely to damage over time.

The insulation type also resists heat as opposed to fiberglass insulation which will burn under extreme heat.

Mineral wool insulation is produced substantially stronger than fiberglass, making it semi-rigid and able to withstand more pressure.

The rigidity makes it a perfect insulation choice for exterior walls among the new environmentally-friendly homeowners.

Fiberglass, on the other hand, is fluffier and weaker because of the production materials and process. This attribute makes it easier to handle and install than most of its counterparts and also makes it one of the best choices for buildings that aren’t rectilinear in shape. However, you should also expect it to be a lot less durable.

4. Ease of Installation

Generally, mineral wool and fiberglass insulations are easy to install, and you can do it yourself by watching a few instructions videos online or reading a written manual.

Working with fiberglass is relatively easy as you only need your utility knife, a straightedge, and patience to ensure the insulation is fitted correctly and not overly compressed.

Installing mineral wool insulations isn’t as daunting as it seems if you install it with the right equipment and proper process.

You’ll need to wear protective gear and check the building codes for your jurisdiction to ensure you’re not breaking any laws.

Simply cut and fit the material to your wall or ceiling, and you should be good to go.

The fluffy nature of fiberglass makes it easier to install than mineral wool. You might need external adhesive material to stick it to your ceiling or wall, while you can just fit mineral wool directly, thanks to its rigid nature.

5. Cost

Mineral wool is more expensive than fiberglass and costs 25%-50% more. Coupled with installation, you might need to shell out twice as much as you would pay for installing fiberglass insulation.

The cost for installing fiberglass stands at around $0.88 to $1.64 per square foot. A professional will charge about $300 to $600 to work on a 500-foot section of your home. For mineral wool, you should be looking at spending close to twice that amount for the same space.

A popular question among homeowners is whether the extra cost for mineral wool insulation is worth it. The quality of the installer is instrumental to the quality of installation service you’ll get, no matter the price you paid or the material in play.

Lastly, the durability, ease of installation, rigidity, soundproof nature, and other positive factors contribute to mineral wool insulation’s expensiveness.

6. Health Effects

Earlier in the article, you learned a bit about the health effects of fiberglass and mineral wool installation. Both materials could affect your health negatively if you don’t handle them properly.

The tiny fibers from the materials can irritate your skin, eyes, and internal organs if they come in contact with each other.

To prevent yourself from health hazards, it would help to seek the service of professionals to assist in the installation process. If you must do it yourself, ensure you observe all the necessary safety protocols. Lastly, it would help to look up your country’s building code to ensure you aren’t getting into legal problems.

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