How to Measure Attic Insulation

According to Energy Star, 9 out of 10 homes in the U.S. are under-insulated. Fall is a great time to inspect your attic for proper insulation and add more if necessary. The temperatures are mild and even a small improvement can save you bundles on your winter heating bills.

Continue reading to learn how to measure your attic insulation levels so you know if you need more insulation or not. For help measuring and adding attic insulation, contact the Diamond-Certified Service Champions to inspect your home for sufficient insulation and offer energy-saving solutions for your property.

Measuring Attic Insulation

One easy way to tell if you need more insulation is by looking across the span of your attic. If you can see your rim joists in the attic, it’s time to add some insulation. Your insulation levels should be well above the rim joists.

For a more accurate measurement of proper insulation levels, we recommend using a yard stick or thick measuring tape to determine if you have the proper amount of attic insulation.

Do you need more attic insulation?

Learn how much attic insulation you need with a few simple tools:

  • Boards (to walk/crawl on, if needed)
  • Measuring tape or yard stick
  • Flashlight
  • Hard hat or cap to protect head
  • Safety glasses, gloves and dust mask/protective face mask
  • Phone/camera (to remember and record your measurements)

So, put on a dust mask and gloves and grab your measuring stick or tape and a phone/camera.

Once you have measured a few spots around the attic, calculate the R-value by multiplying the average depth of your insulation (in inches) by the R-value for your particular insulation type:

What you see:

What it probably is

Depth (inches)

Total R-value


 Light-weight yellow, pink, or white



= 2.5 x Depth

 Dense gray or near white, may have black specs

Rock wool


= 2.8 x Depth

 Small gray flat pieces or fibers (from newsprint)



= 3.7 x Depth



Vermiculite or Perlite


= 2.7 x Depth


 Light-weight yellow, pink, or white



= 3.2 x Depth

Source: Energy Star

We recommend a minimum R38, which is usually between 13 and 14 inches of insulation.

What is R-value?

Insulation levels are measured by their R-value. R-value is the measure of thermal resistance, of insulation or building materials and components.

The higher the R-value number, the better your insulation is able to resist heat traveling through it.

How much attic insulation should I have?

Below is a table of Recommended Home Insulation R-Values provided by Energy Star:


 Add the following insulation levels to your attic 


 For uninsulated

 For attics with existing 3−4 inches
 of insulation

 For uninsulated basements
 or crawlspaces


 R30 to R49

 R25 to R30



 R30 to R60

 R25 to R38

 R13 to R19


 R30 to R60

 R25 to R38

 R19 to R25h


 R38 to R60


 R25 to R30

 5 to 8 

 R49 to R60

 R38 to R49

 R25 to R30

If you live in California, the minimum R-value should be R30. For maximum savings and efficiency, we recommend a minimum of R38.

When adding attic insulation, you don’t have to use the same type of insulation that is currently being used. You can mix and match; however, it’s wise to consult with a professional.

We can ensure your home is comfortable year-round by adding a cloud layer of insulation. Learn more about our Signature Comfort Cloud™ Solution.

Service Champions is known for trustworthy, on-time HVAC and insulation service throughout the East Bay, South Bay, and Sacramento areas.

Related Reading