Know Your R-Values

When it comes to understanding insulation, we need to understand the R-value. The R-value measures insulation’s ability to resist heat from moving through it — basically, how effective it is at insulating your home. The R-value of a piece of insulation ranges from R1 all the way up to R60.

Common insulation types, from lowest R-value to highest per inch, include:

• Insulation blankets (batts and rolls).
• Blown-in or loose fill.
• Spray foam insulation.
• Foam board insulation.

The R-value is based on the type, thickness, and density of the insulation material as well as the temperature, moisture levels, and age of the insulated space. If you’re installing new insulation on top of an existing layer, all those factors contribute to the overall R-value of the space you’re insulating.

Generally, the higher the rating, the higher the performance. However, that’s not all that goes into determining how effective insulation will be in a space.

R-Values Are More Than Insulation

Calculating the R-value is based on more than just the insulation’s ability to minimize the conduction of heat — it also incorporates the location where the insulation is used.

For example, the overall R-value of a wall or ceiling will be slightly different from that of the insulation itself. That’s because heat moves differently — and sometimes, more easily — through materials like studs, shingles, and joists.

The way the insulation is installed matters, too. Insulation that is compressed won’t live up to the full power of its R-value.

What R-Value Do I Need?

Installing insulation with a proper R-value for your space is one of the most efficient and cost-effective moves you can make to lower home heating and cooling costs.

While there’s no quick answer to this question, there are a few tips on what to think about when choosing the best insulation for your project.

Different insulation works best in different places. The insulation that you install in your attic might not be the best choice for your basement and vice versa.

Here are a few conditions to consider when determining what insulation is best for your project:

• Geographic location: Use this map to determine what zone you’re located in and the recommended R-value for your project.
• Your heating and cooling system: How your system manages your home climate is important to consider.
• What part of the house you’re insulating: Walls, attics, and roofs all add density to a space in different ways and have proportionally different airflows.