What Does the R-Value Mean for Home Insulation?

One common question we get from homeowners regarding insulation is in relation to the “R-Value”. So let’s dive a bit deeper into this term and answer these questions:

  • What is an R-Value?
  • What do R-Value numbers mean?
  • How do I know what rating to look for in my home?


What is an R-Value?


The “R” in R-Value stands for “resistance”. The R-value of home insulation materials determines how heat resistant the materials are. How much heat, cool air, or moisture is able to pass through the materials affects the insulation dramatically. The R-Value can help project energy savings, increase energy efficiency, and impact the comfortability of your home.


What do R-Value numbers mean?


Typically R-Value ratings can range from 2 to 9 per square inch. The higher the number, the more dense the insulation material will be, and conversely, the lower the number, the less dense the material will be, which affects the permeability.

Highly rated insulation materials are known to be extremely effective in not letting any air or moisture pass through. This is going to be helpful, especially for exterior walls where you want to keep the weather from affecting the interior of your home, like keeping moisture out during our hot and humid North Carolina summers.

Lower ratings mean the insulation materials have higher permeability. This would be more applicable to the interior walls of a home, where the air is able to pass through in order to help regulate the temperature.


How do I know what rating to look for in my home?


The rating you’ll want will depend on the space in which you seek to insulate. An attic will need different insulation ratings than a bedroom, which will need a different rating than a bathroom. Additionally, your goals for the space will affect the insulation material recommended. For example, if you’d like a room to be fully insulated and completely (or nearly) soundproof, this will require home insulation with a higher R-Value so that sound waves don’t travel inside or outside of the room.

At MPI Foam, we offer spray foam insulation. Open-cell spray foam generally has an R-Value of 3.5 and is best used for interior spaces. Closed-cell spray foam generally has an R-Value of 6 and is a great option for exterior walls.


Ultimately, we recommend you seek out a professional in the industry in order to make sure your home is sufficiently insulated with respect to the proper R-Value to your space. If you’re in need of a professional consult, please give us a ring at 844-MPI-FOAM and we would be happy to come take a look.

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