Existing 3 4 inches of insulation.
Suggested r value for attic.
The amount of insulation recommended for your home will vary depending on a number of factors.
While some ceilings in the southwestern part of the united states require a minimum of r 19 insulation most attics or ceiling areas require a minimum of r 38 in the ceiling.
The r value of some insulations also depends on temperature aging and moisture accumulation.
The r value of the insulation for every inch of thickness depends on the type of insulation.
See the department of energy s doe ranges for recommended levels of insulation below.
Add insulation to attic.
Where you live different climates require different insulation r values.
But newer homes in central and southern arizona are insulated to ratings of r 30 to r 38 while newer homes in northern arizona generally have attic insulation at r 60 because of colder winters.
R value is a measurement of thermal resistance and measures the ability of heat to transfer from one side of an object to another.
Recommended insulation levels for retrofitting existing wood framed buildings.
R values of common types of insulation the two distinct types of attic insulation are loose fill material also commonly known as blown in insulation and batting.
You will need a higher r value of insulation if you live in the northeast than if you live in southern california.
Blown in cellulose insulation can carry an r value of 3 2 3 8 per inch of thickness.
When calculating the r value of a multilayered installation add the r values of the individual layers.
The recommended r value for attic insulation in ontario is between r 50 and r 60.
The recommended r value for attic insulation in our area of the country minnesota is 49.
Installing more insulation in your home increases the r value and the resistance to heat flow.
When determining how much insulation you need don t guesstimate calculate.
R value measures how well certain building insulation materials can resist heat.
Depending on where you live and the part of your home you re insulating walls crawlspace attic etc you ll need a different r value.
Typical recommendations for exterior walls are r 13 to r 23 while r 30 r 38 and r 49 are common for ceilings and attic spaces.
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.
