The International Energy Conservation Code (IECC) requires that insulation products be “…installed in accordance with
the manufacturer’s installation instructions….” In practice, manufacturer’s instructions and industry standards are widely
ignored; insulation is often installed with substantial defects. Insulation installers and others who have a stake in the work (builders,
owners, architects, and code officials) do not understand the performance implications of these defects, so there is little market
push to change or improve.

A mechanism has been introduced into for Home Energy Ratings (HERS) to systematically account for insulation performance
degradation. Based on a repeatable and defensible inspection procedure, the inspections provide a tangible reward for
good performance. The inspection procedures outlined below are used by energy rating performance analysis, which closely
parallels the performance path of the 2004 IECC. Adoption of a similar system by building codes could substantially improve
the effectiveness of performance-based codes and improve the performance of new housing stock.

Presented at Thermal Performance of Exterior Envelopes of Whole Buildings X – December 2007

Units: I-P