The higher the r value the better the thermal performance of the insulation.
Adequate attic insulation r value.
There are many ways to retrofit a home with fiberglass and.
When calculating the r value of a multilayered installation add the r values of the individual layers.
Existing 3 4 inches of insulation.
The r value of some insulations also depends on temperature aging and moisture accumulation.
To give you a quick example if you blow in 18 of insulation into your attic with an r value of 3 0 per inch you ve got an effective r value of 3 x 18 54.
The r value depends on the type of insulation its thickness and its density.
Where you live different climates require different insulation r values.
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.
Recommended insulation levels for retrofitting existing wood framed buildings.
Department of energy it s recommended that attics have an r 38 to r 49 or about 12 to 15 of fiberglass or cellulose insulation.
Add the right kind of insulation.
Fiberglass and cellulose insulation have r values of 2 9 to 3 8 per inch while sprayed foam insulation can go as high as 8 0 per inch.
R value is a measurement of thermal resistance and measures the ability of heat to transfer from one side of an object to another.
The higher the r value the better the thermal performance of the insulation.
As a benchmark one inch of solid wood has an r value of 1.
Houses in a cold climate should have a minimum of r 49 in the attic which is equivalent to approximately 16 of fiberglass insulation.
The recommended level for most attics is to insulate to r 38 or about 10 to 14 inches depending on insulation type.
The recommended r value for attic insulation in our area of the country minnesota is 49.
R value is a measure of insulation s ability to resist heat flow.
You will need a higher r value of insulation if you live in the northeast than if you live in southern california.
You can achieve better thermal performance in your attic by adding an additional layer of insulation.
Add insulation to attic.
Your home s age if your home is more than 10 year old you likely need more insulation.
Blown in cellulose insulation can carry an r value of 3 2 3 8 per inch of thickness.
Get an estimate and calculate the payback.
Warmer climates only require an r 38 or higher or about 12 or more.
But on average a home needs 10 14 inches r 38 of insulation as you can see from this image from energystar go v georgia is a combination of zones 2 3 and 4.
