What must occur for insulation to retain its R-value effectively?

For insulation to retain its R-value effectively, it should not be compressed. The R-value of insulation measures its thermal resistance; this value indicates how well the insulation can resist heat flow. When insulation is compressed, it loses its ability to trap air, which is essential for providing thermal resistance. The air pockets within insulation materials are what provide the material's insulating properties. Compressing these materials reduces the thickness of the insulation, thereby diminishing these air pockets and reducing the overall R-value.

Maintaining the original thickness of the insulation enables it to perform efficiently as intended, providing better energy efficiency and temperature regulation within a building. This principle applies to various types of insulation materials, including fiberglass batts, foam boards, and cellulose. Other factors, such as efficient installation or moisture levels, may also affect insulation performance, but the primary concern for retaining R-value is preventing compression.