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Are You Getting the Right Value From Your R-Values?

Insulation is rated on its ability to slow conduction. The “R” in R-value stands for resistance to conductive heat flow. The number that is attached to the R-value is how resistant the insulation is.
House wrapped in a hat and scarf

9 out of 10 homes in the United States are under-insulated. Not only does this make it more challenging to stay comfortable in your own home, but it can also lead to some discomfort in your wallet.

There are many things to consider when thinking about the insulation in your home. 

  • What type of insulation do you need? 
  • What happens if it is installed incorrectly? 
  • How much insulation do you need? 

This article will help you start to answer some of those questions by talking about something that might sound familiar if you have been researching insulation– R-values.

What is an R-Value?

Both science and nature are constantly trying to reach an equilibrium. Such is the case with hot and cold temperatures. Heat will always flow from warmer areas to cooler areas until there is no longer a temperature difference. That means that during the colder months, the heat from your house will be moving to cooler regions like unheated attics, garages, basements, and the outdoors. During the summer, heat flows from the outside to the interior of your house. 

According to an article published by RetroFoam Corporate, “When talking about R-Value, it’s essential to know that it doesn’t really mean the same thing to injection foam or spray foam as it does traditional insulation like fiberglass or cellulose. This is because spray foam and injection foam, like RetroFoam, create an air seal that just isn’t possible with traditional insulation.”

There are three primary ways that heat can flow:

  • Conduction – the transfer of heat through physical contact
  • Convection – the circulation caused when warmer particles move up, and cooler particles move down
  • Radiation – heat traveling in a straight line heating anything in its path that absorbs energy

Insulation is rated on its ability to slow conduction. The “R” in R-value stands for resistance to conductive heat flow. The number that is attached to the R-value is how resistant the insulation is. For example, if you have R-38 insulation, that means that the insulation is 38 times more resistant to heat conduction than if you didn’t have the insulation.

How Do You Know How Much Insulation Is Needed? has a map of the United States that helps you determine your climate zone and a chart that enables you to determine the required R-values for your location. The Carolinas and surrounding areas fall into zones 3 and 4. Walls need an R-value of 13-15, attics need an R-value of 38-60, and crawl spaces need an R-value of 25-50.

*Note: In the table above, CI stands for “continuous insulation” that is applied to the exterior of the wall assembly just inside the cladding.

See the 2021 International Energy Conservation Code for more information on climate zones.

Why RetroFoam?

The most standard types of insulation are loose-fill insulation and insulation batts. Both of these only offer an R-value up to 3.8 per inch. If you have high-density insulation, you may get an R-value of 4.3 per inch. In a standard 2×4 framed wall, you will typically reach an R-value of about 13 when using loose-fill insulation or insulation batts. You may ask the question, “Well, why not cram a bunch of insulation together to get higher R-values?” The answer to that question is that if you install the insulation incorrectly, the R-value suffers. This can happen when insulation is crammed into space or not fitted correctly around objects in the walls, such as wires and pipes. These types of insulation also deteriorate over time. As the insulation deteriorates, so does your R-value.

Now let’s talk RetroFoam. RetroFoam offers an R-value of up to 5 per inch. If you insulated that same standard 2×4 wall with RetroFoam, it could have an R-value of 20 instead of 13. In addition to the higher R-value, RetroFoam injection foam works to create an airtight seal that keeps air from freely moving through the insulation. This means that RetroFoam not only stops heat conduction it also stops convection. This is not something that traditional insulations can provide. RetroFoam also never sags, settles, or has to be replaced. It will last the lifetime of the house. 

Save money. Stay comfortable. Contact a RetroFoam professional to see how we can help.


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