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.
Wall insulation r value requirements.
The r value of thermal insulation depends on the type of material its thickness and its density.
Insulation r value requirements for usa.
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.
Existing 3 4 inches of insulation.
Insulation is rated in terms of thermal resistance called r value which indicates the resistance to heat flow.
Add insulation to attic.
The higher the r value the greater the insulating effectiveness.
Does your home have enough r value.
Note from this chart that the ideal r value differs for each part of your home.
For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed in your attic to reach r 30 if you live in zones 2 or 3.