Fiberglass Attic Insulation R Value

It can be located on a card left by the previous installer printed on the attic insulation or you can measure it yourself.

Fiberglass attic insulation r value.

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. First you ll need to determine your r value. The loss of r value started at a temperature difference of about 32 f. Recommended home insulation r values.

In fact the loose fill fiberglass lost 35 to 50 of its resistance to heat flow at temperature differences of 70 f to 76 f. Input depth of existing blown in insulation in inches. 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.

The higher the r value the better the thermal performance of the insulation. This calculator is to be used as an estimating tool only. R value is a measure of insulation s ability to resist heat traveling through it. As a benchmark one inch of solid wood has an r value of 1.

Achieving greater r values in exterior walls. Insulation level are specified by r value. If the attic is already insulated you ll want to check the current r value. Warmer climates only require an r 38 or higher or about 12 or more.

Houses in a cold climate should have a minimum of r 49 in the attic which is equivalent to approximately 16 of fiberglass insulation. You can achieve better thermal performance in your attic by adding an additional layer of insulation. 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.

R value is a measurement of thermal resistance and measures the ability of heat to transfer from one side of an object to another.