Insulation Foam vs Cellulose: Full Breakdown  

From blanket batts or rolls to convenient sprays or loosely gathered materials with unique qualities, there are many options with insulation. If you’re at a point where you’re open to exploring the possibilities with insulation, two options worth considering are spray foam insulation and cellulose insulation. These solid and reliable forms of insulation both offer uniquely appealing qualities and benefits worth considering.

The Purpose of Insulation and How It Works

Before diving into the foam vs. cellulose discussion, let’s start by briefly going over just what insulation is and why it’s beneficial. The main purpose of insulation is to manage indoor comfort, although the energy-savings potential of insulation is equally appealing for many homeowners today. Typically, insulation works by slowing down heat flow or transfer. Regardless of the time of year it may be, heat naturally flows from areas where it’s warmer to places where it’s cooler. Insulation reduces this flow between exterior and interior spaces so cooled/warmed air stays where it’s supposed to stay throughout the year, which results in consistent indoor comfort. The right type of insulation for your particular space has the potential to offer benefits that include:

  • Lower utility bills
  • A reduced carbon footprint by cutting down on energy consumption
  • Consistent indoor comfort
  • A heating/cooling system that doesn’t have to work as hard
  • Better overall health related to improvements with indoor comfort and air quality

Spray Foam Insulation

Spray foam insulation is a type of insulation so-named because it’s sprayed into cavities in a way that creates an airtight seal. Also known as spray polyurethane foam (SPF), it’s a soft low-density material that has sort of a “whipped cream-like” appearance when first applied. Once it “cures” or hardens, however, it has more of a solid, slightly fluffy appearance. Open-cell spray foam insulation is the kind of SPF insulation used for interior applications. Closed-cell spray foam is normally used for exterior applications. However, it’s sometimes used for indoor surfaces in certain situations.

How Spray Foam is Installed

When installing spray foam insulation, you’ll need the proper gear. With spray foam, this means a full protective suit, goggles that wrap around, and chemical-resistant gloves. Also, check to see if surfaces are dry since spray foam doesn’t adhere well to moist surfaces. The recommended application method is to “picture frame,” or apply it around the edges of a cavity first to make sure any voids are filled. Wait a few minutes and fill out the rest of the space. Also, wait until one layer or “lift” cures before applying another layer to avoid reducing the R-value.

R-Value of Spray Foam

R-value is rating system that measures a particular type of insulation’s ability to resist heat flow based on its thickness and unique insulating qualities. The R-value of open-cell spray foam ranges from 3.5 to 3.6 per inch, which equates to an R-value of 13 for a typical 2 x 4 cavity. Spray foam R-value is higher with closed-cell insulation. With form of spray foam, R-value ranges from 6.5 to 7 per inch.

Benefits of Spray Foam

  • Spray foam provides a tight seal that deters moisture
  • It minimizes temperature fluctuations
  • Spray foam insulation has a consistent R-value that usually does not change
  • It reduces the transfer of allergens and other sources of indoor air pollution, which contributes to a boost in indoor air quality
  • It’s durable and long-lasting, which also makes it environmentally friendly

Cellulose Insulation

The oldest form of home insulation, cellulose insulation is a fiber-based type of insulation. It’s typically made from recycled materials. It can be either loose-fill or dense packed. Both forms of cellulose insulation are usually installed with a blowing machine, although it’s also available as batts or blankets. The blown-in form has an appearance similar to lint or fluffy clumps that are grouped together. The batts are solid pieces that are usually grayish with bits and pieces of other colors scattered within the blanket from the various recycled materials used.

How Cellulose is Installed

The most common type of cellulose or blown-in insulation is the loose-fill variety. When this type of cellulose insulation is applied, you’ll need to wear a respirator or dust mask along with safety glasses and gloves. A blowing machine is also needed, which you should be able to rent from a local home improvement center. Once the blower is set up, simply blow the insulation into place. However, don’t pack it down. It’s also fine to slightly over fill when applying this type of insulation since loose-fill cellulose will lose some volume once it settles.

R-Value of Cellulose

The R-value of cellulose insulation can range from 3.2 to 3.8 per inch. This is higher than what’s typical with loose-fill fiberglass, which is the other type of blown-in insulation commonly used. Some manufacturers treat cellulose insulation with an acrylic binder to help with settling, which can decrease the R-value. Blown-in cellulose may also lose some of its R-value over time from natural settling.

Benefits of Spray Foam

  • It’s highly energy efficient when compared to other materials
  • Cellulose insulation is considered extremely eco-friendly
  • It’s resistant to fire, mold, and insects because it’s normally treated with boric acid
  • Health risks associated with working with cellulose are much lower than what’s common with fiberglass and some