What is the R-value and U-value of Earth Blocks?
The R-value, or resistance to heat flow, is the most common used measurement for determining building material’s insulating properties. The greater the R-value of a material, the better it is at resisting heat loss (or heat gain). An earth block wall has very little insulative or R-value. Although proponents of other wall systems point to a high R-value as advantageous due to the ability to resist heat loss or gain, an earthen structure with breathable walls has the advantage of U-value (BTU/hr/ft2/°F). The U-value is based on the materials thermal transmittance abilities given a difference between the interior and outside temperatures. The lesser the U-factor of a material, the better it is at transmitting heat. Consequently, the interior temperature of the building changes slowly. A 16″ adobe wall has a U-factor of .163 compared to .490 for concrete blocks.
