• 5610-B East Virginia Beach Blvd. Norfolk, VA 23502
  • |Contact Us
Call Your Local Pros Today! 757-828-0024

What is R-Value?

If you’ve ever talked to a professional insulation contractor, you’ve probably heard the term “R-value.” Interested in learning more about R-value and what, exactly, it means? Continue reading!

So what is the R-value of insulation? Essentially, the R-value is the measurement of how effective insulation is. It varies, depending on the specific type of insulation’s:

  • Material
  • Thickness
  • Density

What Does R-Value Mean?

The R-value of a type of insulation refers to its resistance to heat flow. Insulation’s job is to stop heat transfer, so the R-value is measuring how good it is at what it’s supposed to do. The R-value is expressed as the thickness of the insulation material divided by the thermal conductivity, which is the material’s ability to conduct heat.

The higher the R-value, the better – and in general, the thicker and denser the insulation, the higher the R-value will be. However, this doesn’t necessarily mean you should always install the thickest, densest insulation. The type of insulation (and how much you’ll install) depends on factors such as where you live, the type of HVAC equipment you have, the areas of your home you need to insulate (learn more about where to insulate), etc.

What has an Effect on the R-Value of Insulation?

The material, thickness and density of a type of insulation aren’t the only factors that have an effect on its R-value. The installation of the insulation is also important. How and where insulation is installed will make a big difference – for example, if the insulation is compressed and installed in a tight wall cavity, its R-value will be different than insulation in a ceiling. Compressed insulation doesn’t provide its full thermal resistance, and heat flows around the insulation through floor studs and joists, which affects how the insulation performs.

This is also why proper insulation installation is critical! To get the highest possible R-value and make sure your insulation does its job correctly – reducing your energy costs and keeping your home more comfortable year round – the insulation needs to be installed the right way. This is why we never recommend do-it-yourself insulation projects!

The right type and amount of correctly installed insulation with an ideal R-value keeps your home more comfortable year round, stopping heat from leaking in during the summer and escaping from your home in the winter.

Also related to the R-value of insulation are the:

  • C-value– used to rate thermal conductance (C-factor = the number of BTUs that pass through a square foot of material with a 1 degree temperature difference for a specified thickness); the lower the C-value, the better!
  • K-value– used to rate a material’s ability to allow heat to pass through it, independent of its thickness; the lower the K-value, the better!

More about C-value and K-value in the next blog post!

If you want to learn more about the R-value of insulation, contact Tidewater Insulators today.

services we offer

We install insulation in new and existing homes.

Energy Audits

We provide energy audits to help homeowners save money and live more comfortably.


We provide comprehensive gutter services for new and existing homes.

Shower Doors

We install shower doors in new and existing homes.

Are You Sure?
Stay on Page
You are about to leave this Tidewater Insulators and enter a third-party site. Tidewater Insulators and Installed Building Products have no control over, and accept no liability, obligation, or responsibility for, the contents or performance of other websites. Any such link does not constitute an endorsement or any representation regarding, the linked website, its content, its owner, its performance, its owner’s products or services, or any forward-looking statements found in.
Leave Page
Stay on Page