Fiberglass Attic Insulation R Value

Recommended home insulation r values.

Fiberglass attic insulation r value.

R value is a measure of insulation s ability to resist heat traveling through it. The higher the r value the better the thermal performance of the insulation. The higher the r value the better the thermal performance of the insulation. The table below shows what levels of insulation are cost effective for different climates and.

This calculator is to be used as an estimating tool only. As a benchmark one inch of solid wood has an r value of 1. As you can see there s some variation in r value depending on the particular type and brand of products used. The loose fill fiberglass showed a significant reduction in r value as the attic got colder and the temperature difference got larger.

Click the button to calculate the approximate r value for this job. Insulation level are specified by r value. You can achieve better thermal performance in your attic by adding an additional layer of insulation. First you ll need to determine your r value.

Input depth of existing blown in insulation in inches. It can be located on a card left by the previous installer printed on the attic insulation or you can measure it yourself. If the attic is already insulated you ll want to check the current r value. R value is a measurement of thermal resistance and measures the ability of heat to transfer from one side of an object to another.

Warmer climates only require an r 38 or higher or about 12 or more. In comparison an inch of blown fiberglass insulation has an r value of 3 1 3 4 and an inch of blown cellulose in an attic has an r value of 3 2 3 7. If it s a new building simply reference the energy code map. Depending on where you live it s recommended that attics have a minimum r value of r 30 in warm climates to r 60 in cold climates.

Achieving greater r values in exterior walls.