By Megan Kramer, Performance Homes Consultant
Since my background is in existing homes, I have years of experience evaluating floor and attic insulation, but did not have the opportunity to look inside the walls very much. The walls of a home have the largest surface area, so poor insulation installation in the walls can have the greatest impact on efficiency.
A common misperception is that heat rises, so the attic insulation is most important. In fact, heat moves toward cold. It will migrate through the path of least resistance to an area that is colder. Any connection to the outside world in a primarily heating climate allows for heat transfer. This includes thermal bridging through framing members and sheathing materials not just air leaks. Proper installation of insulation in the walls is incredibly important.
This is where your third-party verifier comes in. We need to determine if the insulation is Grade I, II OR III. When entered into REMRate this Grade can impact the final HERS Index and eligibility for a variety of certifications and program incentives.
I was recently out to a home and decided even though there are a few places where you can see the framing members when the insulation is lightly compressed, this still qualifies as Grade I. Do you agree? Here are the resources I used to make this determination:
It is not just up to the verifier to make sure insulation is installed correctly. The builder must also understand the importance of proper install and work with a insulation company that offers high quality work. Like most things, it is the relationship building that is most important. We need to work together to create an exceptional team to do the job efficiently, effectively and economically!
It is also important that the insulation be enclosed on all six sides as stated by Insulation Training. “To attain a rating of "Grade I", wall insulation shall be enclosed on all six sides, and shall be in substantial contact with the sheathing material on at least one side (interior or exterior) of the cavity. Exception: the interior sheathing/enclosure material is optional in climate zones 1-3, provided insulation is adequately supported and meets all other requirements.”