Cellulose vs. Spray Foam Insulation

Good insulation can make a difference in your utility bills.

Insulation is a key component in the thermal protection of a home. While fiberglass is the most prevalent variety of insulation, you now have the option to exchange the standard barrier for a new, innovative material. Advances in technology have introduced cellulose and spray foam as viable insulation alternatives. These two types of insulation are both praised as heat flow resistant compositions, but there are marked differences in material, function, installation, range and value.

Material

Cellulose insulation is composed 80 percent post-consumer recycled newsprint. The fiber is infused with non-toxic borate compounds that make it resistant to mold, insects and fire. Since it is a largely recycled product that contains no hazardous chemicals, cellulose insulation has become a premium choice in green home design. The material in spray foam insulation is also non-toxic, but it is liquid based and consists of a polymer and a foaming agent. Spray foam insulation does not biodegrade, expands and contracts along with the house.

How It Works

Cellulose insulation is primarily made up of wood fiber. Because the cellular structure of wood has a natural, extreme resistance to heat, cellulose insulation effectively prevents heat conduction and leakage. With spray foam insulation, much of the material's success is due its expansive properties. A spray foam application completely fills wall cavities with insulation while creating an airtight envelope. Its shape conforms to insulated spaces, thus preventing the formation of cracks and openings that can allow warm air to escape.

Installation

Just like commonplace fiberglass insulation, cellulose insulation requires the services of a contractor. Unlike spray foam insulation, wall cavities need to be given an airtight seal before cellulose insulation is installed. Do-it-yourself spray foam insulation is advisable for small spaces, and consumers can buy their own tanks of insulation from contractors. However, larger spaces should be handled by a professional specialist. Contractors are properly equipped to handle large-scale jobs. You can save time and resources by using their assistance.

Range

Cellulose insulation is available in two basic forms--blown and sprayed. Blown cellulose is made up of dry fibers and applied in open attics and closed wall cavities. Sprayed cellulose consists of damp fiber and it is added to open wall cavities. Blown cellulose is a common retrofit application used in older constructions, while sprayed cellulose is the standard approach in new buildings. Spray foam insulation is available in two types as well, open-cell and closed-cell. Open-cell spray foam insulation contains more gaps of air, whereas the closed-cell kind is more compact and filled with gas. Generally speaking, closed-cell foam insulation has a higher R-value than the open-cell form. R-value is a measurement that indicates an insulation's resistance to heat flow. The higher an insulation's R-value, the greater its thermal efficiency.

Value

When compared to cellulose insulation or even the standard fiberglass application, spray foam insulation is typically the most expensive option on the market. While the product comes with a lifetime guarantee, it may not always be the most fiscally sensible choice. If the product has the same R-value as cellulose or fiberglass insulation, then you will not see a return in your investment in the form of reduced heating and cooling bills. But when it comes to decreasing utility fees and heat loss, an insulation should ultimately be considered for its R-value instead of its composition.

References

• University of Massachusetts at Amherst
• Ask the Builder
• HGTV Pro