Call Today


Call Today


Spray Foam vs Fiberglass: Which is the Better Insulator?

Insulation is one of the most effective ways to reduce your energy bills and maximize indoor air comfort.

According to The Department of Energy, heating and cooling accounts for 50% to 70% of the average American home’s annual energy consumption. Insulating your building will help maintain comfortable temperature ranges all year long, cutting the amount of time you use your heating and cooling systems.

Insulation comes in various forms, sizes, and materials. Fiberglass and spray foam are two of the most popular types of home insulation materials. While fiberglass has been the go-to option for residential insulation, spray foam is one of the latest innovations in the industry. 

In this article, we explore the differences between fiberglass and spray foam insulation and help you decide the right insulation solution for your needs.

What is spray foam insulation?

What sets spray foam apart from other insulation materials is its ability to create a continuous barrier that can cover every crack, crevice, and uneven surface.  This makes it an incredibly effective insulator, so much so that you can expect to break even on your initial investment in 18 months.

Additionally, a spray foamed property requires 1/3 less energy to heat and cool compared to a fiberglass insulated home. 

Types of spray foam insulation

spray foam insulation
  • Open cell – Open-cell spray foam is an extremely lightweight insulation material commonly used for crawl spaces, attics, and open wall cavities. The cells are intentionally left open, resulting in a softer and more flexible foam. Open-cell spray foam creates powerful air seals and has sound dampening capabilities.
  • Closed cell – Cells are densely packed together to completely block air and moisture out. Closed-cell foam is more stable and rigid than open-cell foam, giving it the ability to boost the structural integrity of the building, wall, or roofing system where it is applied.

How does spray foam insulation work?

Spray foam is produced by combining isocyanate and polyol resin. The finished product is a long-lasting foam with distinct airtight and watertight qualities.

The foam immediately expands upon application and dries quickly to block air and water. Some open-cell spray foam stretches up to 100 times its original form to fill every gap and combat air leakage.

What is fiberglass insulation?

Fiberglass is a strong and lightweight material that features a series of delicate fibers which are primarily melted down glass. The glass fibers are joined together with adhesive backing such as paper or aluminum foil that also acts as a vapor barrier.

Fiberglass insulation has traditionally been used for thermal and acoustical purposes in attics, crawl spaces, and wall cavities.

How does fiberglass insulation work?

Fiberglass as an insulator slows the spread of heat and sound in buildings. It resists heat transfer by trapping pockets of air as it moves to colder areas, keeping buildings cool in the summer and warm in the winter.

Fiberglass vs spray foam insulation


Applying spray foam involves spraying a blend of chemicals into walls, ceilings, and heard-to-reach areas. The installation process often requires special equipment and techniques, which is why it’s best to leave it to professionals.

While it may be easier to install fiberglass since it comes in pre-cut rolls or batts ready to be placed in walls, safety should be observed this material’s installation, as it can release tiny fibers that irritate the skin and are harmful if breathed into the lungs. Protective gear for fiberglass installation is recommended.


R-value refers to a material’s resistance to heat flow. The higher the R-value, the more ideal a material will be as an insulator.

Open-cell spray foam boasts a 3.5 per inch R-value whereas closed-cell spray foam has approximately 6.5 per inch R-value.

The R-value of fiberglass insulation is notably lower at around 2.2 per inch. Additionally, spray foam insulation maintains steady efficiency while fiberglass may lose R-value over time.


Fiberglass is the material of choice for those on a budget. Spray foam can cost three times as much as fiberglass insulation.


Spray foam can last over 80 years while fiberglass can function between 20 to 30 years. Note that exposure to excess moisture and/or damage due to human interference can lessen the lifespan and effectiveness of fiberglass.

Your spray foam experts in MN

Fiberglass insulation may be cheaper and easier to install than spray foam, but it is also less durable especially in extremely cold temperatures.

Spray foam, on the other hand, is an almost indestructible material that provides superior sealing and insulation to the entire coverage area. Investing in residential spray foam in MN will not only improve indoor comfort but can also help you save you money in the long run.

At Lange Spray Foam, we use premier foam with the highest R-Value per inch built to deliver great returns and lasting performance. Request an estimate now for effective residential and commercial spray foam insulation in MN

Request Estimate

"*" indicates required fields

What type of job are you inquiring about?*