To ensure a quality installation, there are several things to watch out for when installing loose-fill insulation—whether you do the job yourself or hire a professional. You may create undesirable voids or gaps if you install the insulation at too low a density or if you do not completely fill the cavity. Voids are most likely to occur at the top of wall cavities, above windows, around doorways, and in the corners of ceiling cavities. Voids also occur if the installation holes are improperly located between the vertical framing studs or if there are too few fill holes. Keep in mind, though, that installers’ practices may vary regarding the number, location, and size of installation holes. It may be difficult to achieve recommended R-values with loose-fill insulation in the eave area of the attic. There are insulation techniques that can be used to insulate this area adequately.
When insulation is “fluffed,” or blown in at too low a density, air moves more easily through it. This can result in increased heat loss.
“Fluffing” occurs when insulation is installed to minimum thickness but not to minimum weight requirements. The result 6 is a less dense application of insulation that requires fewer bags. When insulation is “fluffed,” air passes more easily through it. This means increased heat loss. Additionally, the fluffed loose-fill insulation will eventually settle and result in a thinner layer with a lower overall R-value. Fiberglass is more “fluffable” than cellulose or rock wool. Intentional fluffing by unscrupulous contractors has been a problem in some parts of the country. To avoid these problems, compare bids from several contractors to see how many bags they specify. Count the number of bags used during installation, either by you or a contractor, and compare it to the instructions on the bag. The manufacturer should specify the amount of insulation required to obtain a particular R-value per square foot (or square meter) of space.