Comments on: How to Grade the Installation Quality of Insulation

By: Allison Bailes

Allison Bailes — Fri, 06 Jul 2012 19:20:03 +0000

Terry H.:
Terry H.: Yes, the air barrier is included when the rater enters the infiltration rate into the software. Thermal bridges get accounted for when they specify the framing details (type of framing, size of framing members, and spacing). It's not perfect since most ratings are done using the default framing factors built into the software.

Sam Y.: I'm not sure how you're substituting Uavg for R-value and grade, but it sounds like you're going beyond what the HERS Standards call for. Yeah, you're absolutely right about floor insulation. I generally believe that fiberglass batts are a poor choice for framed floors, even though that's mostly what builders use.

John N.: That's a great idea! Do you use it on every rating inspection? Or do you find that you're able to assign a grade without it most of the time?

Debbie: Yes, I didn't mention that in the article above, but whenever the rater cannot see the insulation, it's got to be entered as Grade III. Thanks for bringing that up.

Bob: Actually, spray foam is subject to the same grading protocol, as are all types of insulation. I've seen Grade I batts and Grade III spray foam. See my article from a couple of years ago called 4 Pitfalls of Spray Foam Insulation.

Jerry F.: If you're using fiberglass batts, yes, Grade I is very difficult. As you noted, adding some continuous insulation helps to make up for the defects and is the only way to qualify a home for ENERGY STAR Version 3 if it doesn't get Grade I.

By: Jerry Flach

Jerry Flach — Fri, 06 Jul 2012 18:40:31 +0000

From our experience, we've
From our experience, we've concluded that unless insulation artists, Grade 1 insulation is next to impossible as such we make up for it by adding 1 inch of continuous STYROFOAM to the outside of the building in Climate Zone 5.

By: Bob

Bob — Fri, 06 Jul 2012 05:09:13 +0000

Using spray foam resolves
Using spray foam resolves these issues.

By: Debbie

Debbie — Thu, 05 Jul 2012 23:23:43 +0000

if insulation is not
if insulation is not inspected it is consitered grade 3.

if it was manditory that an intermediate inspection of insulation then we would have less problems with insulation.

at the same time the thermal bypass check list could be done.

By: John Nicholas

John Nicholas — Thu, 05 Jul 2012 21:00:54 +0000

Allison, For my Energy Star
Allison, For my Energy Star Homes, I have a piece of scrap Polycarbonate. About 15 inches by 3 feet. It is marked off with a Sharpie to show square feet and inches. Since I already know, from the plans, the square footage of the walls, this makes the measurement easier.

By: Sam Young

Sam Young — Thu, 05 Jul 2012 19:54:44 +0000

I've found it easier to
I've found it easier to figure out the Uavg and use that value for both HERS modeling and Manual J for some parts of the house.

For whatever reason, code officials don't think floor insulation needs to achieve anything close to its R-19 rating at Grade I. The real result is more like R-2 - R-5. The builders don't care to fix it in Georgia. However, they'd never get away with it in California.

When in doubt, go with what the homeowner will "see" in their energy bills!

By: Terry Hill

Terry Hill — Thu, 05 Jul 2012 19:12:49 +0000

Allison,

Allison,

Does the HERS rating account for both an air barrier as a separate, distinct layer and the impact of thermal bridges?