Insulation Learning Center


 Insulation is measured by its thermal resistance or R-value. "R" is the insulations resistance to heat flow. R-value insulation ratings are used to measure insulations ability to resist heat flow. The higher the R value, the more effective the insulation. House Insulation should be purchased based on its R value, not thickness or weight.

R-Value Facts:

  • One type of insulation maybe thicker or thinner, but if the R value is the same they should insulate equally.
  • R value performance testing is done in a 70 F environment with no air movement.  
  • 1 inch of insulation is = to 30 inches of concrete.
  • The R value in house insulation is substantially lowered when there's any air or water/moisture leaks.
  • The standard R value for house insulation varies based on climate and temperature

   The U.S. Dept. of Energy has established minimum recommended insulation R-values for six distinct parts of the country, or insulation zones. Our service area is located in zone 4.


TRC is proudly serving customers in these areas

Angier R-Value

Cary R-Value

Clayton R-Value

Durham R-Value

Garner R-Value

Knightdale R-Value

Pittsboro R-Value

Rolesville R-Value

Wake Forest R-Value

Youngsville R-Value

Apex R-Value

Chapel Hill R-Value

Creedmoor R-Value

Fuquay Varina R-Value

Holly Springs R-Value

Morrisville R-Value

Raleigh R-Value

Sanford R-Value

Wendell R-Value

Zebulon R-Value


Chatham County R-Value

Durham County R-Value

Lee County R-Value

Johnston County R-Value

Orange County R-Value

Wake County R-Value



Contact us directly at (919) 924-7600




Insulation Resources


Did You Know?

Progress Energy offers credits on your energy bill for upgrading your homes insulation

Learn more >>

Did You Know?

Cellulose insulation is made of recycled newspaper


Fiberglass insulation is made of 20% recycled glass