What is Polyurethane foam’s R-Value?
Efficiency Plus has an R-value of 3.5 per inch. The polyurethane spray foam industry has subscribed to a realistic indication of R-value that takes into account the variables that insulation could be subjected to over time in a “real situation” application. This measurement of R-value is called “Long Term Thermal Resistance” LTTR. Other insulation products are tested in controlled conditions in a lab and take into account only heat transfer over a prescribed time. They do not present an accurate indication of how they are expected to perform over time in real “in place” conditions.
