What is Insulation ‘R-value’?
Insulation doesn’t only keep your home warm in the winter and cool in the summer – insulation can help lower your energy bills, prevent mold growth and also keep unwanted noise out.
Related reading: 5 Common Ways We Waste Energy in Our Homes
How well insulation works is expressed by its R-value. An R-value measures the resistance to the flow of heat (also known as thermal resistance).
A higher R-value provides more insulation. Across the U.S., recommended R-values for proper insulation range from R13-R60, depending on whether you are insulating floors, attics, or walls.
What does a higher R-value mean?
Insulation R-values vary based on the type, thickness and density of the insulation material. The higher the R-value, the greater the insulating power – which increases energy efficiency and climate control in the home. However, your home doesn’t necessarily need the highest R-value insulation.
The R-value needed to insulate a home depends on a few different factors:
- Type of insulation material being used (i.e. fiberglass, cellulose, foam)
- The space being insulated (i.e. walls, attic)
- Local climate
Related reading: Understanding Home Energy Loss [Video]
How much insulation is required for your home?
To illustrate the various recommended R-values across the U.S., the Energy Star map below highlights the insulation levels for retrofitting existing wood-framed buildings.


Note: All of Alaska is located in Zone 7, except for the following boroughs in Zone 8; Bethel, Dellingham, Fairbanks N. Star, Nome, North Star, Northwest Arctic, Southeast Arctic, Southeast Fairbanks, Wade Hampton, Yukon-Koyukuk.
Optimizing insulation is a key player in achieving greater energy efficiency savings. Home Energy Audits can help lead the way to discover where to start!