Insulation Ability
Note: the whole-wall R-value ratings are from tests conducted at Oak Ridge National Laboratory.
How well do straw-bale walls insulate compared to more conventional wall systems?
Straw-bale walls have nearly three times the R-value of conventional 2x4 walls, and double the R-value of 2x6 and structural insulated panel (SIP) walls. In terms of insulation ability, straw-bale walls are clearly the better option.
What is the impact of this higher R-value?
Materials with higher R-values are better insulators, and are therefore, better at maintaining appropriate indoor temperature levels. Temperature is the most important climatic factor affecting health and comfort. In addition, higher R-values translate directly into lower heating/cooling costs. Compared to conventional 2x4 walls, straw-bale walls have a third of the heating/cooling costs; compared to 2x6 or SIP walls, straw-bale walls have half the heating/cooling costs. Increased comfort levels and lower heating/cooling costs are two of the major advantages of straw-bale wall systems over more conventional wall systems.