Agriboard's Inflated R-value Claims

Agriboard Industries’ widely publicized R-values of its compressed-straw panels—R-14 (RSI-2.5 for 43⁄8”-thick (110 mm) panels and R-28 (RSI-4.9) for its 77⁄8”-thick (200 mm) panels—are more than 55% inflated according to unpublished information EBN has obtained. In an article on straw as a building material published in May 1995 (EBN Vol. 4, No. 3),  EBN challenged the company’s R-value claims as highly exaggerated. In a follow-up letter, Agriboard vice president Bill Thompson defended the numbers, promising that actual testing would be done soon.

That testing has now been completed for many months, yet results have not been released by Agriboard or the testing organization. Meanwhile, articles about Agriboard’s otherwise excellent products continue to list the exaggerated R-values, as did the company in a telephone inquiry in late December.  EBN editors have learned that the actual R-value for the 77⁄8”-thick panel is approximately R-18 (RSI-3.2), not R-28 (RSI-4.9). Information on the thinner panels was not obtained, but it is probably about R-10 (RSI-1.8).