All About Insulation R-Values (2024)

Insulation ratings are measured inR-valuesper inch of thickness.An R-value tells you how well a type of insulation cankeep heat from leaving or entering your home. R-value insulation ratings vary based on the type, thickness and density of the insulation material. Typically, a higher R-valuemeans better climate control and better energy efficiency for your home.Itusually means a higher price point as well.

For every type and material of insulation, check the R-value per inch of thickness that the manufacturer has listed.In general, the insulation’s method of installation can give you an idea of how it compares to other types of insulation.

Here are the installation methods from lowest to highest averageR-value per inch:

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

Note that the material the insulation is made from will change the R-value as well.

Tip: Radiant barriers and vapor barriers are not rated by R-values.

Your home doesn’t necessarily need the highest R-value insulation. The R-value your insulation needs depends on your local climate.

Themapaboveshowseach region of the U.S.and theDepartment ofEnergy’scorresponding climate zone.Once you find your home’s zone on this map,youcanuse the below R-value insulation chart todetermine the minimum R-value your insulation should have.

Find your zone on the map and then use theabove insulation R-valuechart to determine the level of insulation you need to properly insulate your attic, walls, floors and crawlspaces.These R-values are a sum, meaning this should be the totalR-value once you add up the entire depth of insulation. For example, if you have a type of insulation that has an R-value of R-5 per inch of thickness, you will needa depth of6-inchesof this insulation installed inyour atticto reach R-30if you live in Zones 2 or3.

Note from this chart that the ideal R-value differs for each part of your home. The ideal attic insulation R-value is different than the ideal wall R-value insulation. Make sure your home is properly insulated in all these locations.

As with attics or anywhere else in your home, adding more layers of insulation to your exterior walls is key to having a higher R-value and better thermal performance. Foam board insulation is easy to install between wall studs and over existing blanket insulation.

Spray foam insulation, however, behaves a little differently than other types of insulation. It’s great for sealing gaps around windows and doors because it creates an air seal. Adding more layers won’t increase its performance. Instead, you need to be sure an air seal is created. Spray foam insulation R-value varies, based on manufacturers, which product you choose factors unique to the type of foam. Spray foam insulation R-value is lower for the lighter, open cell foams compared to the denser, closed cell foams. But the R-value can decrease as the foam ages and breaks down, or if the foam gets moisture in its pores.

In addition to attics and exterior walls, you can get greater R-values for your home by remembering to insulate these areas as well:

• Crawlspaces: Next to attics and exterior walls, crawlspaces and basem*nts have the most potential for heat transfer. Be sure that these areas are also adequately insulated.
• Garage: Better temperature control in your garage means you can safely store more items and protectyour car from overly hot or cold temperatures. Garage insulation is easy to install yourself.
• Water heater and water pipes:Adding insulation to your water heater can reduce standby heat losses by 25- to 45-percent, which in turn reduces your energy bills. Wrapping hot water pipes in tubular insulation will also help reduce loss in water heat.
• Ceiling: Enjoy better floor-to-floor climate control in your home by installing ceiling insulation.