Which factor is affected negatively when insulation is compressed?

When insulation is compressed, the R-value, which measures the thermal resistance of insulation, is negatively affected. The R-value is directly related to the thickness and density of the insulation material; it indicates how effectively the insulation can resist heat flow. When insulation is compressed, its thickness decreases, leading to a reduction in its ability to trap air, which is essential for insulating properties. This results in a lower R-value, meaning less effective insulation.

Airflow, moisture resistance, and sound absorbency can also be influenced by compression, but the most significant and direct impact in terms of performance relates to the R-value. A lower R-value means that a building will be less energy-efficient, as more heat can escape or enter the structure, leading to higher energy costs for heating and cooling.