Spray foam insulation is a superior insulation product that overcomes several disadvantages of other insulation products. Spray foam can provide a more uniform, consistent thermal barrier as well as provide air flow retarder functions. To best obtain spray foam’s potential benefits, and overcome it’s higher initial costs, spray foam insulation should be used in a systems approach to creating a better building. In a roof application, spray foam will increase the structure’s ability to handle high winds as well as bring the attic into the conditioned space. A roof application of spray foam insulation will reduce infiltration and reduce ceiling heat transfer and duct losses. Wall and floor applications will also create better thermal and air barriers, and make better use of engineered products. Spray foam insulation can result in less conductive, convective and radiant heat transfer, lower infiltration rates, less duct losses, a more structurally sound building and can result in significantly smaller-sized heating and cooling systems and better comfort levels for the occupants.
The R-value test does not account for air movement or any amount of moisture. Therefore, the test ignores real world conditions such as wind and water vapor. The stated R-values of fiber based insulation are only achieved in an absolute zero wind and zero moisture environment. Given the nature of air and water movement in our homes and properties, the real R-value is typically 50% of the advertised level. Spray foam insulation is the only insulation that blocks air infiltration and also serves as a vapor barrier. By creating a uniform, seamless insulated surface, spray foam is far superior to all of the alternatives.
Same Wall Viewed With IR Thermal Camera:
Camera shows heat loss through fiberglass
Typical Fiberglass Install:
Gaps, Compressed, Missing Fiberglass
The US Department of Energy recommends ranges of R-values based on your location. Insulation is measured in R-values—the higher the R-value, the better your walls and roofs will resist the transfer of heat. In order to provide more realistic evaluations of insulation systems, Oak Ridge National Laboratories developed a large scale, attic climate simulator that could provide data on how efficiently insulation systems rated R-values matched up to more real life performance. The tests results demonstrate that both low density and medium (2 lb) density spray foam insulation installed to the underside of the roof deck in attic assemblies maintain a much higher effective R-value at both low and high temperatures than the fiberglass insulation system. The spray foam insulation systems maintained 74% and 83% respectively of reported R-value at low outside temperatures compared to 46% for the fiberglass assembly, and 61% and 67% of reported R-value at high outside temperature compared to 51% for the fiberglass assembly. Oak Ridge National Laboratory research shows that “perfectly installed” batts lose 11% of their labeled R-Value, and that “commonly installed” fiberglass batts lose 28% of their labeled R-value.
Spray foam insulation claims a couple benefits. First, they fill gaps and voids better. Second, they perform well as air flow retarders. The result is a higher in-the-wall R-value. Infiltration is also reduced, so that component of a building’s energy use is reduced. Both of these benefits result in raising the “effective” R-value of spray foam when compared to typically installed loose fill or batt insulation. Spray foam insulation circumvents floor insulation problems through its ability to completely fill voids and open spaces. Areas around wiring and plumbing as well as open webs of floor trusses can be completely filled, resulting in a complete, essentially uniform thermal barrier on the floor. Spray foam will also create an effective air flow retarder layer on the floor, which will reduce the house air by crawl space air.