For batt-type insulation, which factor most directly affects its performance?

• A. Density
• B. Cost
• C. Aesthetics
• D. Installation practice

Answer: (D)

Installation quality governs batt-type insulation’s performance. The material has a rated R-value per inch, but that value only matters if the batt fills the cavity and blocks air flow as intended. Compression, gaps, or misfits around outlets, around corners, or at joints create air paths that bypass the insulation, dramatically reducing the actual thermal resistance. Installing the batt so it’s not compressed, fits snugly to the cavity, and leaves no gaps or voids—while sealing around penetrations—lets you realize the insulation’s designed performance. Cost or aesthetics don’t directly change heat transfer, and while density affects some physical properties, it’s the workmanship of installation that most directly determines how well the insulation performs.