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Technically Speaking: Not All Insulation is Graded Equally

About a year ago, I worked along with other HERS raters and the North American Insulation Manufacturers Association (NAIMA, a.k.a. Insulation Institute) to conduct a study on the importance of insulation installation quality and grading.

RESNET, the nation’s leading home energy efficiency network and the governing body of the Home Energy Rating System (HERS® Index) established standards for grading insulation installation.

The grading is as follows:

Grade I— the best and nearly perfect install which includes almost no gaps or compression… what some would call “G.O.A.T.”
Grade II—allows for up to 2% of missing insulation (gaps) and up to 10% compression over the insulation surface area… what some would call “mad decent”.
Grade III—insulation gaps exceed 2% and compression exceeds 10%… anything worse and the insulated surface area is considered un-insulated.

RESNET Insulation Diagram

Source: RESNET Mortgage Industry National HERS Standards

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