What effect does compression have on the R-value of insulation?

Compression of insulation directly decreases its R-value, which measures the thermal resistance of the material. When insulation is compressed, the air pockets that contribute to its insulating properties are reduced. Insulation materials rely on trapped air to slow down heat transfer; hence, if the material is tightly packed or compressed, it loses its effectiveness. This is particularly relevant for batt or blanket insulation types, which depend on maintaining their thickness to maximize air space.

Furthermore, the principle behind insulation effectiveness is that materials must maintain their intended thickness to provide optimal thermal resistance. Compressed insulation compromises this thickness, leading to a reduction in R-value and, consequently, decreased energy efficiency in the building. Therefore, recognizing the importance of maintaining the intended thickness of insulation is crucial for ensuring proper thermal performance in structures.