Home Insulation: Achieving Grade 1 Installation
Providing a Grade 1 installation is important to delivering a quality, energy-efficient home. A Grade 1 designation means that the home insulation is properly installed and without any moderate or substantial defects. While Grade 1 installation should be the norm in the residential building industry, there are instances where it is not. The result of a sub-par installation is a home that doesn’t perform to its potential—which unfortunately reflects poorly on builders, installers and insulation manufacturers alike.
What are the RESNET grading criteria?
The Residential Energy Services Network (RESNET) has outlined standards that define an insulation installation grading system for use by HERS raters in evaluating installation quality. When inspecting insulation, HERS raters are primarily looking for any missing insulation (voids), gaps or compression.
Summary of RESNET Grading Criteria:
Grade I – Minor Defects
Occasional very small gaps are allowed. Voids can’t extend from the interior to the exterior (i.e. the full width of a wall cavity). The product is installed according to manufacturer’s specification and cut to fit around electrical junction boxes and is split around wires and pipes. Compression or incomplete fill amounting to 2% or less, if the empty spaces are less than 30% of the intended fill thickness, are acceptable for Grade I.
Grade II – Moderate Defects
Can have minor compression and up to 2% missing insulation. Can also have moderate to frequent gaps around wiring, electrical outlets, plumbing and other intrusions. It’s important to note that the grading system treats and assesses missing insulation differently than compressed insulation.