The R Value Myth

This article argues that R-value alone is a misleading measure of insulation effectiveness. Here's why:

Testing Problems: R-value tests are conducted in unrealistic conditions with zero wind and zero moisture.

Real-world conditions significantly impact insulation performance, especially for fiber insulations.

Fiber Insulation Issues: Fiberglass and similar materials lose effectiveness when exposed to

·       Wind/air movement

·       Moisture

·       Temperature extremes

Spray-in-Place Urethane Advantages:

·       Creates an airtight seal

·       Maintains effectiveness in real-world conditions

·       Provides its own vapor barrier

·       Often performs better than fiber insulation despite lower R-values

Important Insulation Considerations:

·       Heat loss control

·       Surface temperature control

·       The first inch of spray urethane stops 70% of heat loss

The article concludes that R-value tables should be modified to reflect real-world conditions and include equivalents that account for actual performance rather than laboratory tests

This perspective is supported by multiple case studies where spray urethane outperformed traditional insulation despite having lower R-values, particularly in freezer and cold storage applications.