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How Is Insulation Rated?

If you’ve been researching insulation or read anything about different insulating materials (fiberglass, spray foam, etc.), you’ve most likely come across the term “R-value.” What does this term mean and why is it important? It’s related to an insulation material’s rating!

How Is Insulation Rated?

An insulation material’s R-value is its thermal resistance, and it helps determine the insulation’s effectiveness and the amount needed for a particular area of a home (walls, attic, etc.). The R-value depends on:

  • The material
  • The material’s thickness
  • The material’s density

Keep in mind that the effectiveness of an insulation material’s resistance to heat flow also depends on not only where the insulation is installed but how it’s installed—which is why we never recommend DIY projects!

What Is the Right Insulation R-Value for the Portland Area?

In general, installing more insulation in your home increases the R-value and the resistance to heat flow. But it is possible to over-insulate. You need just the right amount, which is determined by a few different factors, including where you live, where you need to insulate and the type of HVAC system you have.

Insulation Climate Zone

Here in the Portland, Oregon area, we are in zone 4. When there is no existing insulation, ideal attic insulation R-value is R38 – R60. For floors, the typical R-value range is R25 – R30. As mentioned, the region isn’t the only determining factor. Different areas of your home require different R-values. The attic needs a higher R-value than the walls because heat naturally rises and commonly escapes through your attic. Different materials also differ in R-values. For example, spray foam insulation has a different R-value than fiberglass.

Insulation Contractors Serving Portland, OR

This is a lot of information, but you don’t need to remember all of it! This is where the pros come in. A local insulation company can help with specifics. They’ll be able to determine how much insulation you need and recommend solutions for your unique situation and any special cases.

Contact Installed Building Products Portland today to learn more about our services or get a free estimate for your project!


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