UNDERSTANDING INSULATION VALUES

The “R” value of an insulating material, by itself, is not an accurate measurement of insulating effectiveness.

Tests performed by the Oak Ridge National Laboratories (federally funded tests) prove that the “R” value of some insulating materials are reduced by standard installation techniques and age. When measured by Oak Ridge, Fiberglass Batts labeled as R19 when installed in walls, using common installation procedures, measured a R11. Also Oak Ridge measured “R” value in cold temperatures (0 degrees F) and R38 fiberglass batts measured R17.7 – a loss of 53% of the R factor.

New research from Oak Ridge National Laboratories (ORNL) confirms that fiberglass batts in 2” x 4” and 2” x 6” walls provide much less than their stated R-Value. Many builders and homeowners are considering other insulation systems that deliver substantially better performance.

EVEN PERFECT INSTALLATIONS SUFFER

The research team at ORNL’s Building Technology Center first tested “perfectly installed” batts. The batts were precisely cut and perfectly fit to create an ideal situation. Even when installed in this manner, the R-19 batts mustered only an R-13.2 insulation value!

THE REAL WORLD

When the research team installed the batts according to common building practices, the performance was even more disastrous. The tests show that in REAL homes, an R-19 batt only provides an R-Value of R-10.3.

Foam has a dramatically better R-Value than Fiberglass

WE KNEW THIS 20 YEARS AGO!!!

Yes, since at least 1979 when Johns-Manville conducted tests of batt insulated walls. Their results were nearly identical to those from Oak Ridge 20 years later. Wall assemblies built to simulate real world construction and installation revealed that R-19 batts lost from 24% to 49% of their R-Value.

Fiberglass Batts, as commonly installed, are not an effective barrier against heat/cooling loss due to air infiltration.

Only Spray Polyurethane Foam does not change.

  • SPF does not settle, its rigidity actually adds to the strength of the building
  • SPF “R” value remains constant for the life of the building
  • SPF blocks air infiltration — a leading cause of heat/cooling loss
  • SPF is inert, it does not add dust or chemicals into the air

Source: Green Insulation Technologies

In the real world of batt insulation, you'll lose 24 to 49% of the R-Value

Source: Johns-Manville Research and Development Center “Effects of Insulation Gaps”, Nov. 1979.