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ArmorThane Spray Foam Insulation Or Fiberglass Insulation: Which Is Better?

Are you unsure which insulation to choose between, fiberglass and spray foam insulation? 

Insulation is crucial for keeping your home cozy and energy-efficient. Several insulation choices exist, but fiberglass and spray foam have become the front runners for quite some time now. 

So, what sets these two insulation types apart?

Spray foam insulation has a higher R-value than fiberglass, making it a better insulator. Also, spray foam is watertight, while fiberglass cracks under moisture. However, installing spray foam requires a professional, while fiberglass is easy to install yourself.

 

A Head-to-Head Comparison of Fiberglass and Spray Foam Insulation

Your choice of insulation material makes a significant difference in energy efficiency. It affects indoor air quality depending on the substances a given insulation type produces, so you shouldn't take this decision lightly.

Therefore, there are many factors to consider when making this decision.

To decide between the most popular choices: Fiberglass and spray foam, you should consider their R-Value, cost-effectiveness, resistance to moisture, durability, ease of installation, and health effects.  

It's also important to note that fiberglass insulation comes in two types:

  • Batts – blanket-style insulation that can be cut to size and stuffed into a wall cavity.
  • Loose-fill – loose fiberglass pieces that look like pillow stuffing that gets blown into the wall cavity once blanketed with a protective layer of mesh fabric.

Fiberglass vs. Spray Foam

Since the two different types of fiberglass insulation are so comparable, we'll concentrate on the most user-friendly one for DIYers.

So, for the rest of this article, we'll examine how spray foam insulation compares to batt-style fiberglass insulation.

Here is a table comparing spray foam and fiberglass insulation and the more suitable choice based on each of the criteria:

Criteria Spray Foam Fiberglass Verdict
R-value 6 per inch or better  2.2 to 3.8 per inch (2.54 cm) Spray foam is much more effective than fiberglass as an insulator
Resistance to Moisture Watertight Because this type of insulation is not waterproof or even water-resistant, the fiberglass material can be become statured with ambient moisture, making it completely useless at insulating your home. When fiberglass insulation becomes saturated it can also begin to grow mold and deteriorate. Spray foam is better for humid climates
Durability Over 50 years 20 years Spray foam is much more durable
Ease of installation Medium: Requires professional help Easy Fiberglass is better for those on a budget
Cost More expensive Cheaper Fiberglass is cheaper, however, you get what you pay for.
Health risks Generally safe to use if installed correctly. Poor installation increases risks such as skin, eye, and lung irritation Generally safe to use if installed correctly. Incorrect installation causes the risk of inhaling tiny glass that can irritate the lungs Both come with health risks that can be mitigated through proper installation

Let's discuss each of the above aspects in more detail:

R-Value

R-value is typically one of the major deciding factors for builders and homeowners alike.

R-value shows how well a substance resists heat flow. A high R-value means more heat will be required to pass through the material before getting into your home.

According to The Department of Energy, the R-value for Fiberglass ranges between 11 and 38—11 for 3.5-inches thick and 38 for 12-inches thick fiberglass.

On the other hand, the R-value averages for spray foam vary from 3.8 per inch (open-cell type) to 7 per inch (17.78 cm) (closed-cell type). (ArmorThanes ArmorFoam has an R-Value of 6 per inch or better)

Based on the national averages, this means that for a 3.5-inches thick insulation material, you get R-values of 13.30 and 24.5 using either open-cell or closed-cell spray foam averages, respectively. 

In contrast, both foam types offer R-values of 42 and 84 when you buy them in 7-inch sizes.

In other words, spray foam offers higher resistance to heat flow, making it the better choice using this criterion.

Resistance to Moisture

The material used for insulation is also crucial because it must hold up well against moisture. Walls exposed to the elements, such as ones in basements and garages, are especially susceptible to moisture problems.

Because fiberglass insulation is not waterproof or even water-resistant, the fiberglass material can be become statured with ambient moisture, making it completely useless at insulating your home. When fiberglass insulation becomes saturated it can also begin to grow mold and deteriorate.

On the other hand, Spray foam has better resistance to moisture damage than fiberglass insulation. Because of that, spray foam is more effective in humid climates, so if you live in such places, spray foam is the necessary choice.

Durability  

Spray foam lasts much longer. The spray foam will stay in place and doesn’t settle, which can ensure continual performance with little fear of damage. However, fiberglass will need an inspection, and even sometimes will need an upgrade. Spray foam’s sealing qualities can even protect your home from dust, allergens, and pollutants, while fiberglass can get dusty and trigger allergy and respiratory issues.

Ease of Installation

While fiberglass may be cheaper, spray foam tends to have an easier installation process. Fiberglass requires measuring and cutting to fit those wall spaces perfectly, while spray foam easily expands 100 times the original size after a quick spray. This means getting every small corner perfectly without cutting up smaller pieces of fiberglass to fit everything. Not sure which spray foam to buy?

Cost

Fiberglass insulation is cheaper than spray foam. However, remember that you get what you pay for. Spray foam has a better R-value per inch than fiberglass insulation gives.

Besides, spray foam is less likely to harbor moisture. It is also more resistant to damage from thermal stress due to changes in temperatures.      

Health Effects

Both fiberglass insulation and spray foam are generally safe if installed correctly. However, fiberglass is made of glass fibers that can penetrate the lungs, lymph nodes, and other vital organs. It is critical to avoid inhalation of, and skin and eye contact with, spray foam chemicals. Spray form contains isocyanates and other chemicals that require respiratory protection. A PPE evaluation before beginning work is a useful tool for determining the appropriate PPE. PPE includes protective clothing, gloves, eye and face protection, and respiratory protection. 

Let's cover some of the major complaints about fiberglass...

Harmful if You Breathe It

Fiberglass batting gives off glass dust that is harmful when inhaled. If fiberglass insulation is improperly installed, the dust could get into your home's air and affect your family's health.

Fiberglass also tends to retain moisture; when this happens, mold growth is possible and might make you sick if you inhale it. So when installing fiberglass insulation in a wet area—like under the kitchen sink or bathroom shower stall—be sure to use a sealant or spray foam insulation instead.

Needs Protective Gear

Since fiberglass insulation is made of glass fibers, it can be dangerous to your health if you are not working with protective gear.  

You'll need a disposable dust mask and gloves when installing fiberglass insulation or cutting the material open to fit spaces in walls.

It is critical to avoid inhalation of, and skin and eye contact with, spray foam chemicals. On the other hand, spray form contains isocyanates and other chemicals that require respiratory protection. A PPE evaluation before beginning work is a useful tool for determining the appropriate PPE. PPE includes protective clothing, gloves, eye and face protection, and respiratory protection. 

Requires Vapor Barrier

Fiberglass insulation is not a vapor barrier by itself. When used with an improperly prepped construction site with no plastic sheathing to protect the walls from liquid damage, water could leak through your walls.  

Therefore, fiberglass insulation needs a vapor barrier to keep moisture away from your home's framing and finishing.

Sagging Problem

Fiberglass insulation is bulky and heavy, so it can sag into your walls as you install it. If not correctly applied or installed, the same can happen to the cardboard backing.

This brings about several problems, such as:

  • Uneven thermal insulation results in either hot or cold spots within your home.
  • Mold growth that might make you sick.

Allergy Problems

Fiberglass batting is well-known for causing irritable skin reactions like rashes and allergies among people who live with it. Besides, it can aggravate bronchitis and asthma.

 

Which one will get bugs?

Fiberglass! Fiberglass and cellulose can easily be torn apart by pests, while spray foam provides zero sources of food for any pests. So no need to worry about rodents, termites, or other critters crawling in your walls.

Pros and Cons of Spray Foam Insulation

The table above shows that spray foam is the most effective form of insulation; though it's not the most wallet-friendly, it seems to be the best option for your home on multiple fronts. Spray foam can prevent cold air from passing through your house, while fiberglass can have air leakage that will contribute to hotter or cooler temperatures in your home based on the weather. Some spray foams can even reject bulk water when it comes to water damage. Fiberglass, however, can retain water and potentially damage your home.

Let's go over some of the other pros and cons so you can make the most informed decision.

Spray foam is often more costly and messy but provides better insulating value and a tighter seal.

Pros

Efficient

Spray foam insulation is a great way to prevent thermal bridging and improve the efficiency of your home.  

Because you spray it into place, it fills all those tough-to-reach spaces that are difficult to reach, such as around pipes and wires.  

Air and Watertight

Because it's sprayed-in, spray foam creates an airtight barrier between your home and the climate outside so that you can save on heating or cooling costs.  

Another primary reason for using spray foam instead of fiberglass insulation is that it doesn't require a vapor barrier. Instead, spray foam can double as a vapor retarder.

This means that you don't need to protect your framing and finishings with plastic sheathing during construction, making installation easier and saving on materials costs.  

Cons

Higher Upfront Cost

One downside to spray foam insulation is it typically does have a higher upfront cost; it's not cheap because the material is expensive.

 

Health Risks

These chemicals can affect the respiratory system negatively if you inhale them. Therefore, it's essential to wear a protective breathing mask and ensure proper ventilation while installing spray foam for insulation purposes.

 

Is Insulation Toxic and Dangerous? (What You Should Know)

Most insulation is toxic and dangerous with some of its health risks, including breathing difficulties, cancer, and skin, eye, and lung irritation. However, most of these risks can be managed by ensuring you wear appropriate safety gear and that the insulation is installed correctly. 

Here are common insulation types and their associated health risks:

  • Fiberglass: Skin and eye irritation, Stomach discomfort, Sore nose or throat.
  • Asbestos (Banned due to its toxicity): Lung cancer.
  • Cellulose: Irritates mucous membrane, eyes, nose, and throat, causes diarrhea (mostly harmful when it burns).
  • Spray Form: Irritates skin, eyes, and lungs.
  • Rigid form with flame retardants: Headache, nausea, and vomiting.

Caution: Do not use asbestos for insulation. It is illegal and poses severe long-term health risks if inhaled.

Final Thoughts

Again, spray foam may be more expensive, but it is hands down the best option for your home on multiple fronts. Spray foam can stop cold air from passing through your house, while fiberglass can have air leakage that will contribute to hotter or cooler temperatures in your home based on the weather. Fiberglass can retain water and potentially damage your home. For those who wish to have the benefit of thermal resistance and long-term protection, spray foam insulation is the way to go. 

If you would like to get a quote or learn how you can become a certified spray foam applicator, contact us today!