Recommended insulation levels for retrofitting existing wood framed buildings.
Adequate attic insulation r value.
You can achieve better thermal performance in your attic by adding an additional layer of insulation.
Existing 3 4 inches of insulation.
Warmer climates only require an r 38 or higher or about 12 or more.
R value is a measurement of thermal resistance and measures the ability of heat to transfer from one side of an object to another.
As a benchmark one inch of solid wood has an r value of 1.
The higher the r value the better the thermal performance of the insulation.
When calculating the r value of a multilayered installation add the r values of the individual layers.
Blown in cellulose insulation can carry an r value of 3 2 3 8 per inch of thickness.
Add the right kind of insulation.
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 r value depends on the type of insulation its thickness and its density.
Achieving greater r values in exterior walls.
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.
Where you live different climates require different insulation r values.
The higher the r value the better the thermal performance of the insulation.
R value is a measure of insulation s ability to resist heat flow.
Get an estimate and calculate the payback.
The r value of some insulations also depends on temperature aging and moisture accumulation.
Add insulation to attic.
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.
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.
Your home s age if your home is more than 10 year old you likely need more 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.
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.
According to the u s.
You will need a higher r value of insulation if you live in the northeast than if you live in southern california.
The recommended r value for attic insulation in our area of the country minnesota is 49.
