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Which Insulation Type Is Better, Fiberglass or Spray Foam?

Homes are typically insulated to prevent the outdoor air from entering and the expensive conditioned air from leaking out. However, gaps and air leaks make it hard for heat to stay inside or outside the home depending on the season.

This is why proper insulation is important. Apart from enhancing overall indoor comfort, insulation also helps in conserving energy and saving on utilities.

While there are several options for insulation, two types are popular today: fiberglass and spray foam.

Each type has its own pros and cons, so picking which one to install can be tricky. Keep reading to determine which type is better.

What Material Should You Use?

Thermal insulation material - Eco Star Foam

Different types of insulation give different results. And whether you should use fiberglass or spray foam depends on what works best for your project and fits your budget.

The scope of your project will also dictate your price range. A smaller scope of projects means a wider range of options will fit within your budget. This gives you more flexibility in choosing more expensive options.

Which Is Better: Fiberglass or Spray Foam?

Let’s take a closer look at the two. Read on to know which one suits your budget and specific needs better.

Fiberglass Insulation

Fiberglass is probably the most common type of insulation. It is made from plastic filaments fortified with recycled glass that are melted down and processed into thin fibers.

Fiberglass comes in two forms:

  • Loose Fill – This is installed by using a professional blowing machine. It is typically used in filling out tight corners or smaller spaces, especially in older buildings.
  • Batts – This is formed like a blanket of thick sheets or rolls of fibers. It is usually installed by a professional as it can be tricky to customize batts and make them fit in spaces.

Spray Foam Insulation

Spray foam is a chemical-based insulation material that is applied using a sprayer. Once sprayed, the foam quickly expands to fill over cracks and voids to form an airtight seal. It helps in preventing air and moisture from penetrating.

The two types of spray foam are:Technician spraying foam insulation - Eco Star Foam

  • Closed Cell – The cells are completely enveloped with foam so air and moisture are completely blocked out. It provides better control over indoor temperature, adds structural strength to the building and helps with sound reduction.
  • Open Cell – The cells are not completely enveloped with foam, allowing moisture permeability to help contribute in moisture management.

Spray Foam Insulation Vs Fiberglass

Let us now compare the strengths and weaknesses of fiberglass and spray foam. Learn how they fare in terms of cost, installation, life expectancy, risks and benefits.


Generally, spray foam insulation is significantly more expensive than fiberglass insulation. Spray foam insulation can cost around $4 per square foot, with a thickness of 3 inches. For the same dimension, fiberglass insulation can only set you back for around $0.4.

Even if you pay a higher price for spray foam, it leads to bigger savings on heating and cooling costs in the long run. You also pay extra because it lasts a lifetime and can be applied in any imaginable hard-to-reach areas that are not suitable with other types of insulation.

Related: Fill Your Walls With Spray Foam and Watch Your Pockets Fill With Money


Another reason that makes spray foam more expensive than fiberglass is its complex installation. A blend of chemicals are sprayed into the area to be insulated to fill it with foam and create an airtight seal.

Insulation installation - Eco Star Foam

To properly execute this process, precision and expertise are required. This is why spray foam is best applied with highly specialized equipment by professionals. Additionally, it takes around 24 to 48 hours for the spray to cure and off-gas.

Fiberglass insulation is considerably easier to install than spray foam. Pre-cut batts and rolls can be easily purchased and installed by any DIY-er with minimal training. However, it is still best to employ a professional to ensure the effectiveness of the insulation. Also, the process can be tricky and time-consuming if you don’t have the expertise. Since the process is fairly straightforward, it has zero downtime.

Life Expectancy

Both spray foam and fiberglass are durable and long-lasting forms of insulation.

Spray foam does not break down easily and can last as long as 80 years or more. It can hold up against moisture so you practically never have to reinstall insulation again.

Fiberglass, on the other hand, has the potential to last for 100 years if it won’t get exposed to moisture. Otherwise, it will lose its effectiveness and lessen its lifespan. When there’s a lot of humidity, you might have to install a new one every decade.

Effects And Risks On Health

During installation, spray foam poses a lot of health risks when protective gear and materials are not properly worn. It can trigger asthma attacks, irritate the eyes, and cause long-term respiratory irritation. But once cured, spray foam is non-toxic and does not pose any health risks.

Fiberglass also poses some health risks during installation as it contains glass wool fibers. It is believed to be carcinogenic. Also, it can cause irritation on eyes, skin, nose, and throat. But like spray foam, there are no known health risks associated with fiberglass insulation once installed.

Moreover, when it comes to blocking sound, pollen and dust once installed, spray foam does a better job at it.

Related: Breathing Made Easier by Spray Foam Insulation

Which Type Of Insulation Will Deliver The Best Value For Money?

Ultimately, both spray foam and fiberglass is so much better than no insulation at all.

But in deciding which type of insulation to install, you must consider cost-effectiveness together with the scope of your project and budget.

Surely, fiberglass insulation can help you save in initial cost but it does not provide an airtight seal to mitigate air leakage. This will reflect on your energy costs and maintenance costs.

On the other hand, spray foam can be more expensive and requires more effort to install, but it offers stronger overall insulation power. In turn, your heating and cooling systems won’t need to work as hard. Energy costs can be significantly reduced and offset its initial cost in no time.

Spray Foam Is Better

Close up view of technician - Eco Star Foam

While fiberglass is not a bad option at all based on the comparisons we made above, it is easy to see why spray foam is better and more cost-effective.

It provides air sealing like no other and it practically lasts forever with little to no maintenance.

If you need to insulate many complicated and hard-to-reach areas, or you live in a place with high humidity, or budget is not an issue, you should install spray foam insulation.

This will ensure that you will get the most insulation with your buck.

More from Star Spray Foam

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Star Spray Foam insulation is proud to provide affordable, efficient insulation services to the community of New Orleans. We have built a reputation in the NOLA area for efficient, high-quality insulation at an affordable cost.

We use quality materials to maximize the amount of heat retained inside your home – and we install them for you hassle-free. Contact us now!