Spray Foam Comparison

With an understanding of the five insulation decision criteria you are ready to make your own evaluation. If you are only concerned about controlling conductive heat loss, then we would suggest that you look at the lower cost alternatives of fiberglass or cellulose insulation. If the other decision criteria are important to you, then we invite you to continue reading our report. The remainder of the report will show you how the different insulation types compare against each of the five decision criteria. CnR Insulation carries both open and closed-cell spray foam products. The closed-cell product is used for specialty applications such as tight spaces and extra high humidity applications such as indoor pools. The remainder of this report will compare these products against traditional insulation types.

Comparing Heat Transfer Control

As you can see in the table below, open-cell foam is about the same as cellulose and fiberglass at controlling conductive heat transfer. Closed-cell foam has about double the ability to control this type of heat loss or gain. You should note that the Dept. of Energy reports that dry cellulose settles up to 20% and fiberglass 2-4% over time, which implies you need to add 20% more cellulose in attic applications ( you cannot do that for wall applications ) . Either type of spray foam will not settle over time. Cellulose can also settle more if it becomes wet and will lose a significant amount of its R-value

The last column of the  table shows the air permeability ASTM E283 test results. The numbers show that both open and closed-cell foam all but stops air flow, which makes both products excellent convective insulators. We could not find test results for either cellulose or fiberglass, but a study by Energy Design Update shows open-cell spray foam is the best at stopping air flow.

Product R-Value Perm Value
Open-cell Spray Foam 3.8 0.008
Closed-cell Spray Foam 7.0 0.001
Cellulose 3.8 Not Found
Fiberglass Batts 3.7 Not Found

Comparing Building Safety Measures

As stated in the earlier part of this report, a Class 1 or Class A fire rating is an important decision criteria. The table to the right shows both open and closed-cell foam are meet the class 1 fire rating criteria of a flame spread index of <= 25 and smoke development index of <= 450. Craft paper backed fiberglass insulation does not report these numbers, probably because the paper will catch fire. Cellulose is recycled news paper, which is treated with a flame retardant such as boric acid.  It has been reported that the boric acid looses 28% of its effectiveness after two years. Also, boric acid in cellulose has been reported to become corrosive after becoming wet. Additionally, tests conducted by the California Bureau of Home Furnishings and Thermal Insulation have demonstrated that some cellulose samples failed the standard fire safety test only six months after installation.

Comparing Health Measures

The results of the ASTM C1338 standard tests whether the insulation material will support mold growth. Again, both open and closed-cell cellulose do not report any mold/mildew growth. Non-paper backed fiberglass will not support mold/mildew growth. Paper is growth media for both mold and mildew. It is well known that mold/mildew can grow on the commonly installed paper-backed fiberglass insulation. Cellulose is treated with a fungicide chemical, but we could not find any reported ASTM test results. Also, we could not find the specific fungicide that is used or any long-term studies about the health affects of the fungicide on building occupants. Both cellulose and fiberglass are known to have particulate matter that can become airborne.

Comparing Environmental Impact

The largest positive environmental impact that insulation can provide is based on the energy usage reduction. Both types of spray foam insulation can reduce energy utility usage/costs by 50% – 70% in newly constructed homes, as compared to traditionally fiberglass insulated homes.


We hope that you have found the information in this report useful, and we thank for taking the time to read it. We believe our spray foam insulation products provide you with a significant value for your money. Spray foam insulation is a premium building product, because it address several building factors. We hope you agree with us and decide to allow us to help with your building project.