Skip to main content
#
Questions? Call!

Residential Energy Efficiency Blog

How to Check the R-Value of the Insulation in Your Attic
Thursday, July 23 2020

If you are having comfort issues in your home a good place to start when looking for answers is the attic.  You must identify what insulation material exists and measure the insulation level in inches to see if you are meeting the latest building codes.  Determining these two things will provide you with enough information to figure out the R-value of your insulation. 

R-value is the conventional method by which the performance of insulation is measured.  Insulation has one job - to resist heat flow.  The higher the R-value, the better the insulation resists the transfer of heat.

Insulation is very important because in summer, insulation stops the hot attic air from coming inside (it gets 150 degrees in attic!!) and in the winter it keeps the warm conditioned air from going outside (through the ceiling mostly, due to pressure).  The attic is the most important place to check first, however there are other areas that should also be considered such as the basement, overhangs and crawl spaces.
 

1st - Determine what Type of Insulation You Have

Different attic insulation materials yield different R-values based on how many inches are in place so one important piece of information to determine insulation R-value is to identify the type of insulation that was installed in your attic.  Fiberglass batts, loose fill fiberglass, loose fill cellulose, mineral wool and foam are all insulation materials that you might find in your attic.

Pop your head up in the attic and take a photo of your insulation. 

Feel free to email it to me so I can take a look and identify it for your eric@hometrustremodeling.com or refer to the photos below to try and figure it out.

Cellulose Loose Fill - Grey in color, more dusty and clingy than fiberglass loose fill, has bits of newspaper in it

attic insulation Maryland


Fiberglass Batts - Typically referred to as rolled insulation, has the kraft paper or aluminum foil on one side.

Insulation Company Maryland     Maryland Attic Insulation Company


Fiberglass Loose Fill - You might see it in your attic in white, yellow, pink or grey.  Much less dusty, but not as good as cellulose!

Insulation company Maryland   Home Insulation Contractor Maryland


2nd - Determine a Reasonable Insulation Level in Inches

Insulation levels in an attic are rarely aligned.  In order to gain an true perspective on how much insulation an attic needs will depend on the cumulative amount in inches an attic has.  So, as an example, if you have an attic that has 8" of insulation at the highest point and 2" at the lowest point and after surveying the attic floor, you can conclude that the level is approximately split 50/50 between the two heights then you can average things and call it 5".  Of course, it is never quite that easy and it take a bit of a trained eye, but another alternative is to simply take measurements in five locations (corners and the middle) and get your number that way.

3rd - Convert the Number of Inches of Insulation into R-Value

Once you determine your type and level, it is time to figure out how to calculate for R-Value.  I won't get into it too much here, but R-Value is sometimes misleading.  This must be said for this reason:  several factors including, installation integrity, the presence of untreated thermal bypasses (cracks/crevices where air can flow through below the insulation) and overall insulation coverage (evenly distributed) all play into the overall R-Value.   

In Maryland, it is recommended that our attics are insulated to R-49

 

For each of the three types of insulation shown in this article (prevalent in Maryland attics), the following R-Values can be multiplied by the number of inches to see where your attic falls on the scale.

  • Loose Fill Cellulose - 3.13 R-Value Per inch (Example: 6 inches of loose fill cellulose = R19)
  • Fiberglass Batt Insulation - 2.10 R-Value Per Inch
  • Loose Fill Fiberglass - 2.73 R-Value Per inch 

Most attics in Maryland are insufficiently insulated and are a big contributor to comfort problems, high energy bills and in some cases, poor indoor air quality.

Comments:

Post comment
Name
 *
Email Address

Message
(max 750 characters)
*
* Required Fields
Note: All comments are subject to approval. Your comment will not appear until it has been approved.

Building Performance Institute Certified
Building Performance Institute
Building Analysts
Envelope Professionals
BGE Approved Energy Contractor
Pepco Approved Energy Contractor

Having your home evaluated by Hometrust is a great way to identify your next home improvement project. 
Certifications earned through the Building Performance Institute demonstrate our ability to:

  • Find air leakage points around your home. 
  • Show you steps to improve energy efficiency.
  • Use science to guide improvements to comfort.  
  • Educate you how to tighten your building's shell. 
  • Learn about these opportunties before it is too late. 
  • Provide a unique perspective on your home's overall performance. 
  • Determine the root cause of any problems.
  • Assess current insulation effectiveness.
  • Measure air flow.
  • Evaluate windows, doors, siding and roofing.
  • Put you in complete control of the outcome.
    Specialized Maryland Contractor
    • MHIC Licensed
    • Building Analyst Certified
    • Envelope Professional Certification
    • EPA Lead Renovator Certified

    Hometrust Remodeling is a licensed contractor specializing in a whole-house approach to home remodeling with an emphasis on educating our customers, providing energy efficient solutions, maintaining a network of high caliber technicians and using building science principles.  As a result, we can effectively guide Maryland homeowners towards projects that satisfy comfort needs, aesthetics and value.

    Service Areas

    Calvert County, Carroll County, Anne Arundel County, Baltimore County, Howard County, Montgomery County, Prince George's County

    Contact Us
    our facebook page
    Hometrust Remodeling
    North Laurel, MD 20723
    301.957.6532
    info@hometrustremodeling.com
    Hometrust Remodeling


    Trust us to put all the pieces together right! 
    ©2020 Hometrust Remodeling | All Rights Reserved