90% of homes in the United States are under-insulated. This can be caused by a myriad of issues, with the most common culprits being: insulation settling over time, construction prior to modern energy codes, lack of upgrades after renovations, compressed or disturbed insulation, and moisture or ventilation issues.
If you suspect that your home may be included in the 90%, there’s a simple insulation inspection you can perform to help determine your insulation needs. Making sure you have the correct amount of attic insulation helps you save money on energy bills, prevent ice dams in the winter, and keeps your house at a comfortable temperature.
How to Assess Your Insulation:
To assess your insulation, go to your attic and measure the insulation depth.
For example, if you are seeing small gray fibers or flat pieces of insulation, you are most likely looking at cellulose insulation. To begin, measure the depth of the insulation. Using that measurement, we will follow this multi-step equation:
Current R-value = (current depth in inches) (R per inch)
Additional R needed = (target R) – (current R)
Additional inches needed = (additional R needed) (R per inch)
In this example, we’ll say the current insulation is approximately 8 inches deep. To achieve an R-value of R-49, you will need to complete the first equation to find the current R-value.
The R-value for cellulose insulation per inch is 3.7, so we put that in the equation too: Current R-value = (8 inches) (3.7). This brings our answer to 29.6.
The next part of the equation is to solve for what additional R-value we need. Our goal is to achieve R-49, so we subtract 29.6 from 49. 49-29.6= 19.4
To determine the final step of the equation (additional inches needed) we will follow the final equation. Taking our additional R needed (19.4) we divide it by R per inch (3.7).
19.4 3.7 = 5.24 inches
Thus, five inches of cellulose insulation will need to be added to your attic to achieve an R-value of R-49.
We’ve included a chart (based on the Ohio, Pennsylvania, and Kentucky climate) to help you determine if your attic insulation is where it needs to be.
| What You See: | What It Probably Is: | R-Value Per Inch: |
| Light weight loose fibers (yellow, pink or white) | Fiberglass | 2.5 |
| Dense gray or near white, may have black specs | Rock wool | 2.8 |
| Small gray or flat pieces or fibers | Cellulose | 3.7 |
| Granules | Light weight vermiculite or perlite* | 2.7 |
| Batt | Batts of insulation | 3.2 |
*care should be taken as this material can possibly have asbestos in it. You should have it tested before disturbing it
Need help determining what you have?
Call North Central Insulation for a free estimate. 419-886-2030
NCI – because saving energy and money makes a difference.
Looking to start your insulation project? Request your FREE on-site consultation with an insulation specialist today!
